The effect of long-term irradiation with fluorescent light on the rat fundus

In the rat, continous exposure to so-called cold light of 800 lux leads to a nearly complete loss of retinal photoreceptors, which occurs within 4 weeks. This process is followed by vascularization of the retinal pigment epithelium (RPE). The origin, extent, and expansion of such proliferations within 6 months after the onset of irradiation were evaluated by means of light microscopy, transmission electron microscopy, scanning electron microscopy, corrosion cast preparation, india ink injection, and trypsin digest preparation. The vessels within the RPE were found to be fenestrated and to form a network with the vessels of the neurosensory retina. Invasion of Bruch's membrane and formation of chorioretinal anastomoses were not observed. The occurrence of vessels within the RPE coincided with a massive regression of capillaries in the neurosensory retina.     

N-Mannich-Base Prodrugs of 5-Iodo-2′-deoxycytidine as Topical Delivery Enhancers

Two Mannich-base prodrugs of 5-iodo-2-deoxycytidine (5-IDC) have been synthesized. The prodrugs exhibit increased lipid solubility compared to 5-IDC and rapidly revert to 5-IDC in buffer. One of the prodrugs delivered about twice as much 5-IDC from isopropyl myristate (IPM) through hairless mouse skin in diffusion-cell experiments as did 5-IDC from IPM. Subsequent applications of theophylline/ propylene glycol onto the diffusion cells to determine the effect of prodrug/IPM, 5-IDC/IPM, or IPM on the resistance of the skins to subsequent applications showed that the prodrug/IPM had no more effect than IPM itself.     

Problems in establishing accurate family history in patients with ovarian cancer of epithelial origin

A detailed family history was obtained from 90 ovarian cancer patients and 90 age-matched controls. Relatives who died in Alberta had their death year and cancer history verified. Year of death was accurate in 12/20 and negative history of cancer in 30/30. Cancer was reported in 229/2,544 relatives. Of these, 104 were or had been residents of Western Canada, but only 69 malignancies were confirmed through population-based cancer registries. This resulted in an error rate of 10/39 (26%) for parents, 7/31 (23%) for siblings, and 18/34 (53%) for uncles and aunts; error rate is similar for patients and controls. A "positive" history of cancer was reported by 53/90 (59%) of patients and 68/90 (76%) of the controls (chi 2 = 5.7); this difference disappears when the total number of relatives is considered: 92/1,179 (7.8%) in patients and 134/1,366 (9.8%) in controls (chi 2 = 3.3). The age of relatives should also be considered for age/sex-specific years at risk comparison. In summary, the validity of studies showing family history of cancer is questionable owing to the multiple sources of error and the lack of specificity of the methods of analysis.     

Significance of preoperative prognosis

The granulocyte phagocytosis test, Karnofsky index, and ASA standard were used in the context of 287 patients for general surgery, for the purpose of retrospective elucidation of the relationship between presurgical prognostication and postsurgical complications. Sensitivity, specificity, and "predictive values" were calculated. The highest information potential in terms of prognostication was recorded from objectively measurable granulocyte phagocytosis. Presurgical prognostication was found to be of clinical relevance only to surgical problem patients.     

Absorption of oral aminoglycosides following bone marrow transplantation

Four patients with severe gastrointestinal reactions receiving oral "nonabsorbable" antibiotics for gut sterilization following bone marrow transplantation absorbed clinically significant amounts of aminoglycoside (gentamicin and/or tobramycin). Serum concentrations of 2.2, 2.6, 5.8, and 12.0 micrograms/ml were measured. Two of these patients had acute graft versus host reactions and two had severe mucositis following cytoreduction with intensive chemotherapy and irradiation. Nephrotoxicity occurred in the latter patients. One patient was studied in detail. Her hospital course and investigative results are presented. Four additional patients with mild gastrointestinal reactions following cytoreduction did not absorb gentamicin when their toxicity was maximal. Serum aminoglycoside determinations are necessary in patients receiving oral aminoglycosides for gut sterilization following bone marrow transplantation if moderate to severe gastrointestinal reactions occur.     

Spinal metastases treated with bipolar radiofrequency ablation with increased (> 70 °C) target temperature: Pain management and local tumor control

PurposeTo investigate the safety and clinical efficacy of bipolar radiofrequency ablation (b-RFA) with increased (> 70 °C) target temperature for the treatment of spine metastases with the intent of achieving pain relief or local tumor control.Materials and methodsThirty-one patients with a total of 37 metastases who were treated with b-RFA with increased temperature and vertebroplasty from January 2016 to May 2019 were retrospectively included. There were 20 women and 11 men with a mean age of 62.4 ± 10.5 (SD) years (range: 40–78 years). Patients and metastases characteristics, procedure details and clinical outcomes were analyzed.ResultsMetastases were predominantly located in lumbar (22/37; 59.5%) or thoracic spine (13/37; 35.1%). Mean target temperature was 88.4 ± 3.5 (SD) °C (range: 70–90 °C). Technical success was 100% (37/37 metastases). One (1/37; 2.7%) major complication unrelated to b-RFA was reported. One (1/37; 2.7%) metastasis was lost to follow-up. Favorable outcome was noted in patients receiving b-RFA for pain management (16/20 metastases; 80%; mean follow-up, 3.4 ± 2.9 [SD] months) or with oligometastatic/oligoprogressive disease (6/6 metastases; 100%; mean follow-up, 5.0 ± 4.6 [SD] months). In patients receiving b-RFA to prevent complications, favorable outcome was noted in 6/10 metastases (60%; mean follow-up, 3.8 ± 4.8 [SD] months).ConclusionsB-RFA with increased target temperature has an excellent safety profile and results in high rates of pain relief and local metastasis control in patients with oligometastatic/oligoprogressive disease. Suboptimal results are achieved in patients receiving b-RFA to prevent complications related to the growth of the index tumor.     

Clonally restricted insulin autoantibodies in a cohort of 2200 healthy blood donors

Summary Serum samples of 2200 blood donors were screened for anti-insulin IgG by enzyme-linked immunosorbent assay. Specificity of detected antibodies was verified by competition with an excess of insulin and observation that saturated anti-insulin IgG were no longer measurable. The upper limit of measured signal in the population was defined as the mean plus three SD. In the direct assay, 32 sera were positive. Among these, 22 (1%) contained saturable insulin antibodies (true positive) and 10 were non-saturable and considered as non-insulin-specific. The positive blood donors were requested to answer a questionnaire and according to their answers, none had ever received insulin, was a first degree relative of a Type 1 (insulin-dependent) diabetic patient or had experienced a hypoglycaemic episode. None of the 22 true positive sera detected by enzyme-immunosorbent assay bound ¹²⁵-I-insulin to any significant extent. The nine sera yielding the highest signal were further characterized with regard to heavy and light chains as well as species specificity of ligand. Anti-insulin IgG from healthy blood donors contained only one heavy (1 2/9; 3 7/9) and one light ( 8/9; 1/9) chain. Three sera were human insulin specific; two were non-species-specific; the other four bound insulin in the order human = porcine > bovine. These results indicate that low affinity clonally restricted antibodies against insulin are present in unselected blood donors with a prevalence of 1%.