Reversal of Cerebral Vasospasm by the Nitric Oxide Donor SNAP in an Experimental Model of Subarachnoid Haemorrhage

The constant release of nitric oxide (NO) is essential to maintain basal cerebrovascular tone. Oxyhaemoglobin, liberated by lysis of red blood cells after subarachnoid haemorrhage binds NO and prevents its entry into vascular smooth muscle cells. While endothelium-dependent vasoconstriction is preserved, decreased levels of NO inhibit endothelium-dependent relaxation and may cause vasospasm. S-nitrosothiols are potent vasodilators and precursors of NO. The authors' aim was to determine whether S-nitroso-N-acetylpenicillamine (SNAP), a stable S-nitrosothiol compound, could reverse vasospasm in an experimental vasospasm model in rabbit. Experimental subarachnoid haemorrhage (SAH) was induced in 37 New Zealand white rabbits. The animals were divided into four groups. Control (no SAH), SAH only, SAH plus saline and SAH plus SNAP. SNAP (15 micrograms/kg/min) or 0.09% saline (equal volume) was infused 46 hours after induction of SAH. All animals were killed by perfusion fixation 48 hours after SAH occurred. Basilar arteries were removed, sectioned and their cross sectional areas were evaluated in a blind manner, by light microscopy and by using computer assisted morphometry. Experimental SAH elicited vasospasm in all animals of SAH only and SAH plus saline group. In animals treated with SNAP, arterial narrowing was markedly attenuated without producing systemic hypotension. This widening achieved statistical significance when compared to the arteries of the SAH only and SAH plus saline group (p < 0.01). This study indicates that the NO donor SNAP is a potentially useful drug to reverse cerebral vasospasm due to SAH.     

The effect of polycythemic hyperviscosity on ischemic bowel necrosis

It is known that polycythemia decreases the fluidity of the blood and impairs tissue perfusion due to red-cell sludging in the microcirculation. In this study, the effect of polycythemic hyperviscosity (PH) on bowel necrosis was evaluated in an experimental model of intestinal ischemia. Twenty-eight Wistar albino rats (90–170 g) were divided into two groups: group 1 was transfused to create hyperviscosity and then intestinal ischemia was produced (n = 16); in group 2 ischemia was produced without transfusion (n = 12). Intestinal ischemia was produced by clamping the superior mesenteric artery and the collateral arcades of the right colic artery for 30 min. Gross and histopathologic evaluations were performed by either immediate necropsy or relaparotomy 24 h later. Microscopic findings were graded from 0 to 3 according to the degree of ischemic changes. In group 1, 2 animals (12.5%) died before 24 h postoperatively; coagulation necrosis with grade 2 or 3 ischemic changes was observed in 10 animals (62.5%). In group 2 only a few hypertrophied Peyer's patches and capillary dilation were found, and all histopathologic changes were between grades 0 and 1. The difference between the histopathologic gradings of the two groups was significant (P < 0.001). It appears that in addition to reduced splanchnic blood flow, a secondary effect of PH is needed to induce ischemic coagulation necrosis. PH of the newborn must be considered a risk factor for necrotizing enterocolitis, so-called spontaneous intestinal perforations, and even intestinal atresia.Presented at the 1st European Congress of Pediatric Surgery, Graz/Austria, May 4–6, 1995     

Hypozincaemia in febrile convulsion

To understand further the role of trace elements in the pathogenesis of febrile convulsions, serum zinc (Zn), copper (Cu), magnesium (Mg) and CSF Zn, Cu, Mg and protein levels were measured by spectrometry in patients with febrile convulsion (n=19), bacterial meningitis (n=9), viral CNS infection (n=16) and in the control groupn=10) which consisted of children with signs of meningeal irritation due to upper respiratory tract infection but normal CSF findings. Samples were obtained within 6 h after admission to hospital. Mean serum and CSF Zn levels in the febrile convulsion group were significantly lower than in the other groups (for serum Zn: 0.66±0.03 mg/l vs 0.98±0.07 mg/l, 1.06±0.08 mg/l, 1.05±0.09 mg/lP<0.05; for CSF Zn: 22.96±1.62 g/l vs 75.47 ±6.9 g/l, 50.32±5.235 g/l, 39.85 ±2.81 g/lP<0.05). A linear relationship was established between serum Zn and CSF Zn levels (P<0.001). Mean CSF Zn, Cu and protein levels in the bacterial meningitis group were significantly higher than in the other groups (for CSF Cu 63.94±6.33 g/l vs 38.77±2.70 g/l, 35.84±3.48 g/l, 33.86±2.88 g/lP<0.05; for CSF protein 0.80 ± 0.12 g/l vs 0.22±0.02 g/l, 0.53±0.08 g/l, 0.19±0.01 g/lP<0.05). In children with meningitis, the elevation of the mean CSF Zn and Cu levels may result from the breakdown of the blood-brain barrier and subsequent leakage of trace elements and protein from serum to CSF. There was no significant difference between the four groups in terms of mean serum Mg and mean CSF Mg levels.Conclusion Serum and CSF Zn levels are decreased in children with febrile seizures. Zinc deprivation may play a role in the pathogenesis of febrile seizures.     

Significance of wet autoclave pretreatment in immunohistochemistry

Until recently the only way to rescue masked epitopes in routinely processed surgical pathological material was enzymatic digestion. The use of heat for antigen retrieval, first by microwave irradiation, represents an important breakthrough in immunohistochemistry. With the acceptance of microwave oven pretreatment, various modified techniques and alternative heating methods have also been proposed. Wet autoclave pretreatment for tissue proteolysis is a highly reliable alternative to the microwave antigen retrieval technique. It provides uniform heating of the slides, hence an even enhancement of staining intensity in a variety of formalin-sensitive antigens, and it also offers consistent interlaboratory results. The method has been introduced in routine diagnostic immunohistochemistry for the detection of estrogen-and progesterone receptors, L26-, Ki-67- and bcl-2 antigens and variable types of cytokeratins (1/5/10/11, 8, 13, 19). Experimentally, wet autoclaving can be used very successfully for the immunophenotyping of p53 and mdm2 expression, for the detection of adhesion molecules (CD44, integrins) and some anti-inflammatory molecules (annexins), among others. It has produced a substantial improvement in the visualisation of silver-stained nucleolar organizer regionsassociated proteins (AgNORs) in routine paraffin sections and along with modified silver staining and standardized AgNOR parameters assessed by image analysis. Wet autoclaving-based AgNOR staining has been proposed by a European multicentric study group as the standardized method for AgNOR analysis in archival material.     

Proliferative (mib1, mdm2) versus anti-proliferative (p53) markers in head and neck cancer. An Immunohistochemical study

Formalin fixed and paraffin embedded samples from 36 squamous cell carcinomas of the larynx and the oral cavity (pT₂N₀M₀, R₀) surrounded by non-tumorous mucosa were studied immunohistochemically using a panel of four different anti-p53 antibodies (CM1, PAbl801, D07, PAb240), a monoclonal anti-mdm2 antibody and MIB1, following wet autoclave antigen retrieval. P53 immunoreactivity was detected in 11/14 laryngeal and in 9/22 oral carcinomas. All p53 positive oral, and all but one laryngeal tumors revealed mdm2 positivity as well, whereas in p53 negative tumors 4/12 and 1/3 mdm2 immunopositive cases were demonstrated, respectively. MIB1 labeling indices of the tumors ranged between 18% – 64% in p53 positive cases, and 10% – 53% in p53 negative ones. The difference was not statistically significant. Close spatial coexpression of p53, mdm2 and MIB1 immunoreactivity was observed at the invasive front of the carcinomas and in the basal and suprabasal layers of the non-tumorous epithelium in all p53 positive cases. However, the MIB1 expression was similarly increased at the invasive margins in carcinomas lacking immunohistochemically detectable p53 alterations. Our results strongly suggest that p53 overexpression does not necessarily correspond to increased rate of proliferation, but rather to mdm2 overexpression and is largely dependent on the anatomical site in case of small and localized squamous cell carcinomas of the head and neck region.     

Videolaparoscopic treatment of liver hydatid cysts with partial cystectomy and omentoplasty

Hydatid disease is one of the world's most important health problems. Although several conservative approaches have been used for the management of this condition, surgery remains the ideal choice in most of the cases. Videolaparoscopic approach can safely be applied for the management of liver hydatid cysts if several precautions are undertaken. In this study, we present two liver hydatid cyst cases successfully treated with partial cystectomy and omentoplasty using videolaparoscopic approach.     

Prevalence of known and hidden alcoholism in the revisited lundby population

Summary Using the new data from a second followup of the Lundby 1947 cohort, the aim of the present paper has been to analyze some relationships between known and hidden alcoholism in a Swedish general population sample. Information was collected by psychiatrists trough free, exploratory field interviews checked against documentary records. Alcoholism was medically defined for present purposes. Information was obtained for 98% of the 952 men surviving the cross-section date July 1, 1972. The distribution of alcoholism and other psychiatric disorders in the total population and in age subgroups was analyzed epidemiologically. The true prevalence of alcoholism in the adult men was 9.5%, comprising 7.2% known and 2.3% hidden. The proportion of hidden to known cases was 0.301 (Temperance Boards 0.871, Psychiatric Agencies 0.961, Drinking and driving offences 4.31). The main finding that about 70% of male alcoholics in Lundby appears to be known to the agencies is at variance with current views that there is an iceberg under the tip, though consistent with Rubington's suggestion that so-called hidden alcoholism is not totally but partially invisible in welfare societies.     

99mTc-gentamicin: Chemical and biological evaluation

^99mTc-Gentamicin complex, a new agent for renal studies, is prepared by the reduction of pertechnetate by stannous chloride. Organ distribution in rats and paper chromatography with Whatman 3MM paper [developed in n-butanol, acetic acid, and water (4:1:1)] were favored as analytical tools for determination of labeling parameters of ^99mTc-Gentamicin. A higher concentration of stannous ion is responsible for the formation of insoluble technetium species which concentrate in the liver. The mean kidney: liver ratio of 10.4:1 was obtained 1 h after injection. This confirms that scintigraphic delineation of kidneys is highly satisfactory.     

Pancreatic tumors in multiple endocrine neoplasia type 1: Clinical presentation and surgical treatment

Among 33 patients with endocrine pancreatic tumors due to multiple endocrine neoplasia type 1 (MEN-1), 19 (58%) patients had hypergastrinemia, 7 (21%) patients had hyperinsulinism, and 7 (21%) patients had clinically non-functioning lesions. At least one gross tumor was found in all patients undergoing pancreatic surgery, including those with negative localization studies prior to operation. The patients also had additional macroscopic tumors as well as numerous microadenomas, and the lesions frequently were positive for immunostaining with multiple hormones, mainly pancreatic polypeptide, insulin, glucagon, and somatostatin. Duodenal endocrine lesions were found in 4 of 5 investigated patients and stained with gastrin and somatostatin antibodies. Distal, mainly subtotal pancreatic resection, was performed in 18 patients, eventually combined with caput tumor enucleation or duodenotomy, while a few patients underwent only tumor enucleation or a Whipple procedure. The long-erm outcome of operation was most favorable in patients with hyperinsulinism; only 1 patient had clinical recurrence. Patients with hypergastrinemia experienced only transitory lowering of serum gastrin values after pancreatic surgery and 47% of them had or developed metastases. Such tumor spread was seen in 57% of the patients with non-functioning lesions. Nine patients died from progressive tumor disease during follow-up. Consistent with previous studies, we found that surgery is indicated in MEN-1 patients with hyperinsulinism even if a lesion is not visualized by radiology. In addition, these indications should be extended to also include patients with only biochemical markers of disease, including elevations of gastrin, as these indicate the presence of gross tumors. This strategy should be applied especially in patients with aggressive family histories to possibly reduce the risk of malignant tumor progression.

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Resumen Entre 33 individuos con tumores pancréaticos endocrinos como componente del síndrome de neoplasia endocrina múltiple tipo 1 (NEM-1), 19 pacientes (58%) tenían hipergastrinemia, 7 (21%) hiperinsulinismo y 7 (21%) lesiones clínicas no funcionantes. En la totalidad de los pacientes sometidos a cirugía pancreática fue hallado por lo menos un tumor, incluso en aquellos con examenes de localización negativos anteriores a la operación. Estos pacientes también albergaban tumores macroscópicos, así como numerosos microadenomas; con frecuencia las lesiones demostraron inmunocoloración con diferentes hormonas, principalmente polipéptido, insulina, glucagón y somatostatina. Se encontraron lesiones endocrinas duodenales en 4 de cada 5 pacientes investigados, las cuales colorearon con gastrina y anticuerpos a la somatostatina. Se practicó resección pancreática distal (principalmente resección subtotal) en 18 pacientes, eventualmente combinada con enucleación del tumor (cuando éste se hallaba ubicado en la cabeza del páncreas) o duodenectomía; solamente unos pocos pacientes fueron sometidos a simple enucleación del tumor o al procedimiento de Whipple. El resultado a largo plazo fue más favorable en los pacientes con hiperinsulinismo, puesto que sólo uno presentó recurrencia clínica. Los pacientes con hipergastrinemia exhibieron apenas una disminución transitoria de los valores de gastrina sérica luego de la cirugía pancreática. Cuarenta y siete por ciento del conjunto tuvo o desarrolló metástasis, en tanto que la extensión local del tumor se presentó en 57% de los casos con lesiones no funcionantes. Nueve pacientes murieron por progresión de la neoplasia en el curso del seguimiento. En acuerdo con sugerencias previas, se considero quo la cirugía está indicada en pacientes con NEM-1 e hiperinsulinismo, aún en los casos en que no se visualiza radiológicamente la lesión, pero que la indicación puede ser ampliada para incluir también pacientes con sólo marcadores bioquímicos, tales como niveles elevados de gastrina, indicativos de la presencia de tumores macroscópicos. Esta estrategia debe ser aplicada principalmente en aquellos pacientes con historia familiar agresiva, con lo cual tal vez se reduce el riesgo de progesión maligna del tumor.

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Résumé Parmi 33 patients ayant une tumeur pancréatique endocrine due à une néoplasie endocrine multiple de type 1 (MEN-1), 19 (58%) avaient une hypergastrinémie, 7 (21%) un hyperinsulinisme et 7 (21%) une lésion cliniquement muette. On a mis en évidence au minimum une grosse tumeur chez tous les patients, y compris chez ceux dont les examens préopératoires de dépistage tumoral étaient négatifs. Les patients étaient également porteurs de tumeurs macroscopiques et de nombreux microadénomes. Les lésions montraient souvent un immunomarquage positif pour de multiples hormones, principalement le polypeptide pancréatique, l'insuline, le glucagon et la somatostatine. Des lésions endocrines duodénales furent retrouvées chez 4 des 5 patients explorés; elles montraient un immunomarquage avec les anticorps angigastrine et anti-somatostatine. Une résection pancréatique distale, le plus souvent subtotale, a été réalisée chez 18 patients. Elle était éventuellement complétée par une énucléation tmorale de la tête ou par une duodénotomie. Peu de patients ont bénéficié d'une simple énucléation ou d'une intervention de Whipple. L'évolution postopératoire à long terme a été plus favorable en cas d'insulinome puisque seul un patient a eu une récidive clinique. Les patients atteints de gastrinome n'ont présenté que transitoirement une diminution des taux sériques de gastrine après la chirurgie pancréatique. Quarante sept pour cent de ces patients avaient ou ont développé des métastases contre 57% des patients porteurs de lésions sans traduction clinique. Neuf patients sont décédés en raison de l'extension tumorale au cours du suivi. Conformément à des suggestions antérieures, la chirurgie semble indiquée chez les patients atteints de MEN-1 avec hyperinsulinisme même si la radiologie ne visualise pas de lésion. Mais cette indication peut être élargie aux patients dont seuls les paramètres biologiques sont en faveur d'une grosse tumeur (dont l'hypergastrinémie). Cette stratégie pourrait convenir particulièrement aux patients ayant des antécédents familiaux importants; elle permettrait peut-être de réduire le risque d'extension tumorale.

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Presented at the International Association of Endocrine Surgeons in Stockholm, Sweden, August, 1991.