The long-term outcome of volar plate arthroplasty of the proximal interphalangeal joint

The ultimate effectiveness of an arthroplasty is most accurately determined by a long-term review of the joints' function and freedom from pain. We examined 17 patients an average of 11.5 years (range, 4-26 years) following volar plate arthroplasty for a fracture-dislocation of the proximal interphalangeal joint. All surgeries were performed by the same surgeon. The average age was 36 years (range, 17-61 years). No patient complained of pain at rest or with activity. Patients having arthroplasty within 4 weeks of injury attained a total active range of motion of 85 degrees (50 degrees to 110 degrees ). Patients having arthroplasty more than 4 weeks after injury (average, 20 weeks) included several elderly women and averaged 61 degrees (30 degrees to 90 degrees ) total active range of motion. Four patients showed some degree of joint narrowing at the follow-up examination. This review suggests that volar plate arthroplasty continues to be of benefit on a long-term basis and provides satisfactory function and pain-free motion.     

Behaviour and physiological responses during prone and supine sleep in early infancy

AIMS: To study the effect of prone and supine sleep on infant behaviour, peripheral skin temperature, and cardiorespiratory parameters to aid understanding of why prone sleeping is associated with an increased risk of sudden infant death syndrome. METHODS: Of 33 enrolled infants, 32 were studied at 2.5 and 28 at 5 months of age. A computer aided multichannel system was used for polysomnographic recordings. Behaviour was charted separately. RESULTS: Prone REM (active) sleep was associated with lower frequencies of short arousals, body movements and sighs, and a shorter duration of apnoeas than supine REM sleep at both ages. At 2.5 months there were less frequent episodes of periodic breathing during prone sleep in non-REM (quiet) and REM sleep. Heart rate and peripheral skin temperature were higher in the prone position during both sleep states at both ages. CONCLUSIONS: The observation of decreased variation in behaviour and respiratory pattern, increased heart rate, and increased peripheral skin temperature during prone compared with supine sleep may indicate that young infants are less able to maintain adequate respiratory and metabolic homoeostasis during prone sleep.     

Nitric oxide inhibits neonatal hepatocyte oxidative metabolism

BACKGROUND/PURPOSE: Liver function is frequently impaired in neonates with sepsis. Nitric oxide (NO) is thought to be a mediator of organ dysfunction and liver oxidative metabolism during sepsis. The authors developed an in vitro model to investigate the effect of NO and the combined effect of NO plus H2O2 on neonatal hepatocyte oxidative metabolism. METHODS: Hepatocytes were isolated from neonatal rats. Oxygen consumption was measured polarographically. In Study A, cells were exposed to S-Nitroso-N-acetylpenicillamine (SNAP), an NO donor, at various concentrations. In study B, myxothiazol and oligomycin, inhibitors of mitochondrial respiration, were added to investigate the site of action of NO. In study C, hepatocytes were incubated in the presence of both SNAP (300 micromol/L) and H2O2 (1.5 mmol/L). In study D, morphological alterations induced by NO and NO plus H2O2 were investigated by hepatocyte electron microscopy. RESULTS: In study A, SNAP caused a dose-dependent decrease in oxygen consumption. A significant inhibition was reached at 300 micromol/L SNAP. In study B, the lack of further inhibition when SNAP was given together with myxothiazol indicates that NO acts intramitochondrially. Similarly, no further inhibition occurred when the NO donor was given together with oligomycin, suggesting that the effect of NO is mainly at the level of ATP synthase. In study C, concomitant addition of 300 micromol/L SNAP and 1.5 mmol/L H2O2 to hepatocytes caused further inhibition of oxygen consumption compared with either SNAP or H2O2 alone. In study D, mild alterations in hepatocyte morphology were noted in the presence of SNAP or SNAP plus H2O2. CONCLUSIONS: In neonatal hepatocytes, NO significantly inhibits mitochondrial oxygen consumption, possibly at the level of ATP synthase. The effect of NO is additive to that of H2O2. Morphological findings were consistent with these biochemical effects and suggest that NO and H2O2 are important mediators of liver damage during sepsis.     

COMPLEMENT FIXATION IN HUMAN MALARIA WITH AN ANTIGEN PREPARED FROM THE MONKEY PARASITE PLASMODIUM KNOWLESI

In the studies of complement fixation described in this paper, the antigens were prepared from (a) normal monkey red cells, (b) parasitized red cells of monkeys dying with Plasmodium knowlesi infection, (c) the spleens of monkeys dying with Plasmodium knowlesi infection; the sera came from (a) normal human beings, (b) patients with syphilis, (c) patients with paresis who were receiving malaria therapy with Plasmodium knowlesi, Plasmodium vivax, or Plasmodium falciparum, and (d) patients with malaria alone. The malarial antigens gave negative complement fixation reactions with 70 to 80 per cent of the luetic and normal sera and weak or doubtful reactions with the remaining 20 to 30 per cent. With the exception of one antigen prepared from spleen, there was no evidence that the malarial antigens were more reactive with Wassermann-positive than with Wassermann-negative sera. Some human sera give weak complement fixation with antigens prepared from normal monkey erythrocytes, and the percentage of these positive reactions is slightly higher with malarial sera than with normal or luetic sera. The most sensitive and specific malarial antigen was prepared from dried parasitized red cells by extraction with saline, freezing, and thawing. This P. knowlesi antigen gives strong complement fixation with malarial sera from human beings infected with P. knowlesi, P. vivax, or P. falciparum. The titer of complement-fixing antibodies reaches a maximum about 1 month after the beginning of the acute infection. At this time all of the P. knowlesi sera tested were positive. After 4 months the reaction diminishes rapidly in titer but may remain positive for 12 months or longer. With P. knowlesi infections in man, the complement fixation reaction remains positive for some time after the infection has apparently disappeared as judged by daily smears and inoculation of monkeys with the blood. The complement fixation reaction in malaria is group-specific rather than species-specific. Sera from patients infected with P. vivax or P. falciparum react in the same way with the P. knowlesi antigen as the homologous sera. Absorption of malarial human sera with normal monkey erythrocytes does not remove the immune bodies which fix complement with malarial antigens.     

Laparoscopic Ladd's procedure for malrotation in infants and children is still a controversial approach

BackgroundOpen Ladd's procedure is the gold standard for the correction of intestinal malrotation and laparoscopic approach remains controversial. This study aimed to evaluate our experience in laparoscopic management of malrotation.MethodsSingle center retrospective study including patients who underwent a laparoscopic assessment of intestinal malrotation with correction if appropriate between 2007 and 2017.ResultsSixty-five patients (median age 7 months) had a laparoscopic assessment with and without correction of malrotation. Forty-five (69%) were symptomatic, including 16 (25%) with a midgut volvulus. The procedure was completed laparoscopically in 55 (86%) patients in 110 min (30–190). Conversions happened more frequently at the beginning of the experience. With a follow-up of 12.5 months (8 days–5.3 years), morbidity rate was 15% and 4 (6%) patients underwent a redo surgery, all in the first 5 months after surgery, compared with 3/53 (6%) in a contemporaneous group undergoing open Ladd's.ConclusionThis is the largest series reported so far of the laparoscopic management of malrotation. Laparoscopic Ladd's procedure is reliable but still exposes to open conversion which may be in part owing to a learning curve. A low conversion threshold is important in cases with volvulus. The redo rate is similar to that of the open procedure.Level of evidenceLevel III retrospective comparative treatment study.     

Equivalent squares for small field dosimetry

The use of equivalent squares is of value when determining output and depth dose data for rectangular fields. We have looked at the variation with field shape of head scatter factors (S(c)), phantom scatter factors (S(p)) and tissue phantom ratios (TPRs) using measurements on a 6 MV linac with a Moduleaf mini-multileaf collimator. Measurements were made for fields with dimensions down to 1 cm. A different approach to calculating equivalent squares needs to be made depending on the quantity of interest. For TPRs, good agreement for rectangular fields can be obtained using the well established E = 2XY/(X+Y) formula where E is the equivalent square field size and X and Y are the field dimensions. For S(c) measurements, where a collimator exchange effect is observed, better agreement is obtained using E = (1+A)XY/(AX+Y), where A is an empirically determined constant. For S(p) measurements, E = 2XY/(X+Y) only gives agreement with measurements when the minimum field dimension is at least 2.5 cm. For smaller fields, the equivalent square overestimates S(p), with the difference being strongly related to the value of the smaller dimension. We propose an empirical formula, based on the size of the smaller dimension.     

Intestinal ischemia-reperfusion injury does not lead to acute central nervous system damage

BACKGROUND: The detrimental effects of intestinal ischemia reperfusion (IIR) injury on secondary organs including the liver, lungs, heart, and kidney have been widely investigated in animal models. However, the effect of IIR on the central nervous system (CNS) is largely unknown. We investigated the effect of IIR on the CNS as it may be of clinical relevance to patients at high risk of neurological injury. MATERIALS AND METHODS: Adult male rats underwent IIR (60 min superior mesenteric artery occlusion followed by 120 min reperfusion, n = 7) or sham operation (n = 6) under anesthesia. Following the procedure, the cerebral hemispheres were removed for histological assessment and measurement of N-acetyl-aspartate (NAA), a marker of neuronal damage, by HPLC. Blood was taken for determination of plasma S100B concentration, a measure of glial cell damage by ELISA. Data are median (range). RESULTS: Cerebral tissue from all animals from both groups was macroscopically and microscopically normal with no evidence of inflammation. NAA in brain homogenate was similar in the IIR group (0.2 [0.1-0.32] nmol/mg protein) and sham-operated group (0.19 [0.12-0.34], P = 0.83). Plasma S100B levels were higher in the IIR group compared to sham-operated animals but this difference was not statistically significant (1.13 [0.24-7.26] versus 0.55 [0.23-2.84] mug/l, P = 0.18). CONCLUSIONS: In this model, IIR injury did not produce histological CNS changes nor biochemical changes suggestive of neuronal damage. Further work is required to elucidate any functional effect of IIR injury on the CNS.