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Biomedical subjects

C Wolff

Publications and source records attributed to C Wolff.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Prevalence of hepatitis C virus antibodies in a hemodialysis unit].

The prevalence of hepatitis C antibody was studied using the EIA 2 Abbott assay in patients and staff of the San Juan de Dios Hospital Hemodialysis Unit. The antibody was detected in 29.8% of patients, no member of the staff had positive antibodies. Patients with a positive antibody had been on hemodialysis for a longer time than those with a negative test (53.3 +/- 18.8 vs 37.9 +/- 33.5 months respectively). No differences in the number of transfusions received were observed between patients with positive or negative antibodies. Hepatitis B surface antigen was detected in 2 patients, with negative hepatitis C virus antibody. No clinical evidence of liver disease was found among patients with positive antibodies.

Acute Kidney Injury↗
PubMed1993

[Rheumatoid arthritis. Therapeutic efficacy of methotrexate and its hepatotoxic effects].

The efficacy and toxicity (specially hepatic) of methotrexate in low doses (7.5 mg/week) was prospectively assessed in 21 patients with rheumatoid arthritis refractory to treatment with gold or penicillamine, during two years. Three patients were prematurely withdrawn from the protocol. A fast and significant improvement of RA was observed during the first six months, which tapered thereafter. Erythrocyte sedimentation rate decreased from 51.5 +/- 20.1 to 27.7 +/- 11.5 mm/h (p < 0.05). A rise in serum transaminases, always raising to less than twice the normal value, was observed in 75% of patients in some moment of the follow up. Hepatic scintigraphy did not show significant changes. Hepatic histological alterations were mild and no changes were observed after two years of treatment. The main secondary effects were moderate and transitory gastrointestinal and hematological disturbances. The prednisone dose was decreased from 6.8 +/- 2.6 to 4.8 +/- 1.9 mg/day at twelve months. There were no withdrawals due to drug toxicity. It is concluded that methotrexate proved to be efficacious in the treatment of rheumatoid arthritis refractory to conventional treatments. Its secondary effects, although frequent, were discrete and transitory and there were no changes in liver histology.

Adult↗
PubMed1993

[Prevention of digestive hemorrhage recurrence in hepatic cirrhosis with propranolol. A 4 years' follow-up study].

The aim of this study was to assess the effect of propranolol treatment on the recurrence of variceal bleeding and mortality in patients with hepatic cirrhosis. Fifty seven patients were studied; they were recruited within 15 days of an episode of variceal bleeding, assigned randomly to receive propranolol (n = 29) placebo (n = 28) and followed during 4 years. Three patients were lost from follow up and in 3 propranolol was discontinued due to secondary effects. Bleeding recurrence was less frequent in the treated patients (Kaplan Meier analysis p < 0.01). Ten patients on placebo and 1 receiving the active drug died. Life table analysis showed a significantly better survival in the group of patients treated with propranolol. It is concluded that propranolol decreases the recurrence of variceal bleeding and improves survival in patients with hepatic cirrhosis.

Adult↗
PubMed1992

Immunoglobulin preparations from hepatitis C antibody-positive plasma donors: influence on diagnosis and risk of infection in heart transplant recipients.

All heart transplant patients in our clinic received intravenous immunoglobulins as a prophylaxis against cytomegalovirus infections or reactivations. Serum was sampled from 160 heart transplant patients within 4 months after surgery. In 98 samples (61%) hepatitis C virus (HCV)-specific antibodies could be detected by a "second generation" enzyme immunoassay. Of these HCV antibody-positive patients 89 were tested for a second time. At this time, 5-11 months later, in 66 patients (74%) the HCV antibody had disappeared. In the 23 still positively reacting patients, immunoglobulins were given in the last 6 months before serum sampling. Nine commercial immunoglobulin preparations were tested for HCV-specific antibodies and the presence of HCV RNA. Seven preparations were anti-HCV positive with titres in the range of 64-256, whereas reverse transcription and polymerase chain reaction did not detect HCV RNA in any immunoglobulin preparation. Passive antibody transfer rather than a HCV infection is the cause of HCV antibody detection in our patients. The presence of HCV antibodies in high concentrations in commercial immunoglobulin preparations may only be explained by an extremely high proportion of anti-HCV-positive single donations in the plasma pools used for immunoglobulin production. The passive HCV antibody transmission prevents anti-HCV serological monitoring of patients treated with these preparations. Additionally, there are reports on the transmission of hepatitis non-A, non-B via immunoglobulin preparations. Therefore, we recommend an anti-HCV screening of plasma donors.

Blood Donors↗
PubMed1992

Decreased incidence of extra-alveolar air leakage or death prior to air leakage in high versus low rate positive pressure ventilation: results of a randomised seven-centre trial in preterm infants.

Two different ventilation techniques were compared in a seven-centre, randomised trial with 181 preterm infants up to and including 32 completed weeks gestational age, who needed mechanical ventilation because of lung disease of any type. Technique A used a constant rate (60 cycles/min), inspiratory time (IT) (0.33s) and inspiratory: expiratory ratio (I:E) (1:2). The tidal and minute volume was only changed by varying peak inspiratory pressure until weaning via continuous positive airway pressure. Technique B used a lower rate (30 cycles/min) with longer IT (1.0 s). The I:E ratio could be changed from 1:1 to 2:1 in case of hypoxaemia. Chest X-rays taken at fixed intervals were evaluated by a paediatric radiologist and a neonatologist unaware of the type of ventilation used in the patients. A reduction of at least 20% in extra-alveolar air leakage (EAL) or death prior to EAL was supposed in infants ventilated by method A. A sequential design was used to test this hypothesis. The null hypothesis was rejected (P = 0.05) when the 22nd untied pair was completed. The largest reduction in EAL (-55%) was observed in the subgroup 31-32 weeks of gestation and none in the most immature group (< 28 weeks). We conclude that in preterm infants requiring mechanical ventilation for any reason of lung insufficiency, ventilation at 60 cycles/min and short IT (0.33 s) significantly reduces EAL or prior death compared with 30 cycles/min and a longer IT of 1 s. We speculate that a further increase in rate and reduction of IT would also lower the risk of barotrauma in the most immature and susceptible infants.

Barotrauma↗
PubMed1992

Improved detection of hepatitis C virus RNA by reverse transcription and polymerase chain reaction.

The polymerase chain reaction with prior reverse transcription of RNA into cDNA was applied to hepatitis C virus RNA detection in human serum samples of different origin. In order to eliminate false negative results, the following steps were optimized: RNA extraction, reverse transcription, and oligonucleotide primer selection. We compared different RNA extraction methods using guanidinium salt/detergent and proteinase K digestion/phenol extraction, and tested virus particle enrichment with polyethylene glycol precipitation and ultracentrifugation. RNA extraction with guanidinium salt/detergent was the most efficient method. Ultracentrifugation of single samples did not improve hepatitis C virus RNA detection. Polyethylene glycol precipitation performed poorly. Recombinant thermostable reverse transcriptase produced cDNA from fewer samples than did Moloney murine leukaemia virus reverse transcriptase. Nested oligonucleotide primers from the 5'-terminal non-coding region of the hepatitis C virus genome amplified cDNA from more samples than did primers from the coding regions. Thirty six anti-hepatitis C virus antibody positive samples were tested; nested primers (nucleotides 6 to 327 and 15 to 288) yielded 21 amplificates, whereas primers from the coding region produced 16 amplificates (nucleotides 4684-5276) and 5 amplificates (nucleotides 5166-5270), respectively. The most efficient combination of steps was RNA extraction with guanidinium salt solution, reverse transcription with Moloney murine leukaemia virus reverse transcriptase and nested polymerase chain reaction primed with primers from the 5'-terminal non-coding region of the hepatitis C virus genome. Other combinations produced more false negative results. Three different groups of anti-hepatitis C virus antibody positive individuals had markedly different viraemia patterns: Hepatitis C virus RNA was detected in the sera of only 10% of anti-hepatitis C virus antibody positive blood donors, but in 90% of anti-hepatitis C virus antibody positive patients with clinically manifest hepatitis C, and 90% of anti-hepatitis C virus antibody positive haemophiliacs who had received plasma products in the past which had not been virus-inactivated. No hepatitis C virus RNA could be detected in the sera of 450 anti-hepatitis C virus antibody negative blood donors with elevated serum alanine aminotransferase catalytic concentrations.

Alanine Transaminase↗
PubMed1992

[Drugs and porphyric crisis].

Life threatening crisis may accompany some varieties of porphyria like the acute intermittent form, coproporphyria, porphyria variegata and that associated to deficiency of porphobilinogen synthetase. Drugs are commonly involved as precipitating factors. A classification of drugs according to their proven or probable triggering effect is offered in this paper. Insufficient information precludes the classification of some drugs.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1992

[The hepatic porphyrias: experience with 105 cases].

Hepatic porphyria is a rare metabolic syndrome caused by abnormal enzyme activity in heme biosynthesis. Between 1974 and 1991; 105 patients have met criteria for diagnosis of hepatic porphyria based on typical clinical findings and/or laboratory abnormalities. According to type, 42% had porphyria cutanea tarda, 21% porphyria variegate, 15% protoporphyria, 6.7% acute intermittent porphyria, 6.7% coproporphyria and 1.9% porphyria due to porphobilinogen deficit. A proper classification was not established in 6.7% of patients. Porphyria cutanea tarda was more common in males (70%) and porphyria variegata, in females (90%). A family history of the disease was present in 33% of patients; 20% of patients were of European descent and 4% of Mapuche descent. Diagnosis was usually established in the third decade, somewhat later in porphyria cutanea tarda (45 years of age) and very early in protoporphyria. 10% of patients were asymptomatic and 29 patients developed at least one porphyric crisis. These were related to pregnancy in 6 patients, to hormone administration in 7, to antibiotics in 5. No cause was established in 21 cases. Severe crisis were successfully treated with Hematin. Venipuncture was used to treat 50% of patients with porphyria cutanea tarda with 95% success. Thus, hepatic porphyria is recognized with increasing frequency and can be treated successfully in most cases.

Adolescent↗
PubMed1992

Cancer in the Caribbean and environs. A comparison of age-standardized rates for 9 population groups.

Age-standardized rates for cancer in Kingston & St. Andrew, Jamaica are presented by site and sex, and compared with data from Registries in the Caribbean and adjacent regions. These comprise Costa Rica, Cuba, Cali (Colombia), Martinique, the Netherlands Antilles (excluding Aruba), New Orleans (Whites and Blacks) and Puerto Rico. There are significant differences which demand explanation. Overall, the reported rates are highest in New Orleans, which leads in breast cancer, tumours of bronchus, larynx, colon, rectum, pancreas, prostate and bladder. Lymphomas occur most frequently in Whites in New Orleans while Blacks in that city show similar rates to other Registries in the area. Cali (Colombia) and Costa Rica lead in cervical cancer, with Jamaica third. The lowest figure is for Whites in New Orleans. Cali (Colombia) and Costa Rica also have very high rates for gastric cancer, and low rates for colonic. Oesophageal cancer is highest in Blacks in New Orleans, followed by Martinique and the Netherlands Antilles. Jamaica has shown a steady decline for this site over 30 years. The rate in Whites in New Orleans is only one-fourth of that in Blacks.

Black People↗
PubMed1991

High rate of false positives in blood donor screening for antibodies to hepatitis C virus. Cause of underestimation of virus transmission rate?

Anti-hepatitis C virus antibody screening of blood donors in different countries revealed prevalences ranging from 0.4-1.4%. These results were obtained with an enzyme immunoassay based on a recombinant hepatitis C virus antigen. We applied a specific inhibition assay (neutralization assay) and a recombinant immunoblot assay to determine the specificity of positive reactions in the enzyme immunoassay. Of 2836 blood donor sera tested, 10 (0.35%) were reactive in the enzyme immunoassay, however, only 3 sera (0.1%) proved to be specifically anti-HCV positive in the inhibition assay. The recombinant immunoblot assay gave similar results. The prevalence of anti-hepatitis C virus antibodies among blood donors has been overestimated in recent publications. Furthermore the high rate of false positives in the enzyme immunoassay may explain reports claiming that only a minor part of EIA positive blood units transmitted the hepatitis C virus to recipients. The inhibition assay was also applied to sera of haemophiliacs and of patients with hepatopathy which had reacted positively in the anti-hepatitis C virus antibody enzyme immunoassay. The anti-hepatitis C virus specificity was confirmed for all sera from the haemophiliacs group (100%) and for 77% of the hepatopathy patients group. Thus, the anti-hepatitis C virus enzyme immunoassay has a high predictive value when it is used to screen groups with high risks of parenteral hepatitis C virus infection, however, its predictive value is very low when it is used for blood donor screening.

Antigens, Viral↗
PubMed1991

Photosensitization of L1210 leukaemic cells by argon laser irradiation after incubation with haematoporphyrin derivative and rhodamine 123.

The selectivity and efficacy of photodynamic therapy (PDT) may be improved by the combined use of photosensitizers in a similar manner to the combined use of drugs in cancer chemotherapy. Two photosensitizers (haematoporphyrin derivative (HPD) and rhodamine 123 (Rh-123) were analysed which can be irradiated at the same wavelength (514 nm), are preferentially taken up by tumour tissue and are not specific for the same target (membrane for HPD, mitochondria for Rh-123). The analysis of the phototoxic effects in surviving fractions showed a dependence on dose for both products and a dependence on incubation time for HPD but not Rh-123. The lethal dose for 50% cell death (LD50) for HPD increased from 25 to 56 J cm-2 when the HPD dose was reduced from 2.5 to 1 micrograms ml-1 for the same incubation time. When the incubation time was increased from 15 to 45 min, the surviving fraction decreased by 37% and 17% for doses of 1 and 2.5 micrograms ml-1 respectively. For low doses (0.5 and 1 microgram ml-1), the toxicity of the two photosensitizers added simultaneously was weaker than for Rh-123 alone, whereas for high doses (2.5 micrograms ml-1) the surviving fraction was less than that obtained with Rh-123 alone. These results were compared with the light energy absorbed, the quantum yield of singlet oxygen and Rh-123 uptake as determined by flow cytometry analysis.

Animals↗
PubMed1991

Hepato-splenic distribution of 99Tcm-phytate and hepato-enteric distribution of 99Tcm-DISIDA in mice with carbon tetrachloride-induced acute liver damage.

The hepato-enteric distribution of 99Tcm-labelled DISIDA and the hepato-splenic distribution of 99Tcm-labelled phytate were studied in controls and in mice with carbon tetrachloride-induced acute liver damage. The test group animals showed a diminished excretion of DISIDA to intestine with retention of this tracer in the liver and an increased splenic uptake of phytate. No changes in the hepatic uptake of phytate were found. The joint evaluation of both tracers in the study of diffuse liver disease is discussed.

Animals↗
PubMed1991

Deficiency of porphobilinogen synthase associated with acute crisis. Diagnosis of the first two cases in Chile by laboratory methods.

Erythrocyte porphobilinogen synthase deficiency was confirmed by the determination of its activity in blood and also by the high levels of both porphyrins and 5-aminolaevulinic acid in the urine of two siblings. They presented with a picture of porphyric attack characterized by abdominal colic pain, high blood pressure, tachycardia and severe constipation. The profile of both porphyrins and their precursors in urine and blood resembled lead poisoning. However, this was ruled out because both patients had normal blood levels of lead. Furthermore, porphobilinogen synthase activity did not normalize when it was determined in the presence of dithiothreitol or dithiothreitol plus zinc chloride. No other causes to account for a deficiency in porphobilinogen synthase activity were identified. The simultaneous occurrence of similar clinical and biochemical symptoms suggests that the same triggering factor was present. Because the activity of porphobilinogen synthase was less than 4% of normal values, it is possible that these patients were homozygotes with respect to this defect, which could explain the presence of clinical symptoms. We propose that this metabolic defect is not uncommon and it should be kept in mind when diagnosing of porphyrias or heavy metal intoxications.

Adult↗
PubMed1991

Age- specific incidence of cancer in Kingston and St. Andrew, Jamaica. Part I: 1978-1982.

A total of 3,396 malignant neoplasms were recorded in Kingston and St. Andrew, Jamaica during 1978 to 1982. There were 1,477 males and 1,919 females. Histological confirmation was achieved in 88.4%. The crude incidence rate for males for all age groups was 107.8 per 100,000 per year; in females, the figure was 123.0. The age-standardized rates (world population) were 157.9 for males and 159.1 for females. Age-specific rates by site, sex, and age are tabulated.

Adolescent↗
PubMed1991

Age-specific incidence of cancer in Kingston & St. Andrew, Jamaica. Part II: 1983-1987.

The Jamaica Cancer Registry recorded 3,652 cases of cancer in Kingston and St. Andrew during the period 1983-1987. Histological confirmation was maintained at a high level (86.3%). For males, the crude rate was 103.1 and for females, 126.5 (per 100,000 per annum). The age-standardized rates for all ages were 148.3 for males, and 160.2 for females. The Tables contain age-specific rates for each site by age and sex.

Adolescent↗
PubMed1991

30-year cancer trends in Jamaica. Kingston & St. Andrew (1958-1987).

A total of 19,225 malignant neoplasms were recorded in Kingston & St. Andrew, Jamaica over the 30-year period 1958-1987. The most prevalent cancers in males were those of prostate (12.2%), stomach (10.9%) and lung (10.7%). In females 24.1% of cancers occurred in breast and 20% were recorded for invasive carcinoma of the cervix. There is a steady improvement in the diagnosis of in situ cervical lesions, and a relative decline in the incidence of invasive lesions. Lung cancer in women remains at a low level. A significant decline in cancer of the oesophagus and stomach in both sexes was noted, while neoplasms of colon and rectum maintained a stable pattern. The 30-year trends of lymphomas and leukaemias have shown no increase, although there are changes in classification patterns.

Adolescent↗
PubMed1990

[Assessment of early postoperative convalescence by a simple scoring system].

Fifty patients in classes 1-2 of the American Society of Anaesthesiologists (ASA) were submitted to major elective abdominal surgery. They were anaesthetised with a balanced technique and were assessed preoperatively and daily until the tenth postoperative day by a simple scoring system based on self-care. The total score fell significantly to a minimum on the first postoperative day and remained significantly decreased but with an increasing tendency until the tenth postoperative day. Patients with wound or respiratory complications had significantly lower scores than patients without complications on the sixth to ninth days. It is concluded that this simple scoring system is useful for monitoring early postoperative morbidity and it may prove of value in future investigations of surgical therapeutic regimes.

Convalescence↗