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Biomedical subjects

G Jacobs

Publications and source records attributed to G Jacobs.

At least 37 records · Page 2Linked to original sources
PubMed1997

Comparison of thoracic radiographs with images transmitted via advanced telecommunications equipment.

OBJECTIVE: To compare thoracic radiographs of clinically normal dogs and dogs with mild clinical heartworm disease with images transmitted by a desk-top, two-way audiovisual teleconferencing system. DESIGN: Prospective, matched-set study. STUDY POPULATION: 50 thoracic radiographs from clinically normal and heartworm-infected dogs and the digitally transmitted images of those radiographs. PROCEDURE: Thoracic radiographs from 25 clinically normal dogs and 25 dogs infected with 1 to 24 heartworms were evaluated by 3 clinicians. Using classic criteria for heartworm disease, evaluations of radiographs and images transmitted digitally over 2 high-speed data-transfer telephone lines (56 kilobits/s/line) were performed. Clinicians were asked to determine whether dogs had radiographic signs of heartworm disease. RESULTS: Clinicians' ability to detect heartworm disease did not differ between interpretations of radiographs and those of transmitted images. CLINICAL IMPLICATIONS: Radiographic images transmitted via a teleconference system can be used to provide reliable diagnostic information. Thoracic radiographs can be interpreted at a remote site permitting rapid consultation and immediate advice on clinical management.

Animals↗
PubMed1997

Clinical and pathologic findings in Doberman pinschers with occult cardiomyopathy that died suddenly or developed congestive heart failure: 54 cases (1984-1991).

OBJECTIVE: To determine echocardiographic, electrocardiographic, and histologic abnormalities in Doberman Pinschers with occult cardiomyopathy that died suddenly and to compare findings with those of Doberman Pinschers with cardiomyopathy that died of congestive heart failure. DESIGN: Retrospective study. ANIMALS: 14 Doberman Pinschers with occult cardiomyopathy that died suddenly (group 1) and 40 Doberman Pinschers with cardiomyopathy and congestive heart failure (group 2). PROCEDURE: Serial echocardiography and continuous, ambulatory electrocardiographic (Holter) monitoring were performed. Hearts of dogs that died suddenly were examined histologically. RESULTS: Group-2 dogs died at a significantly older age than did group-1 dogs. All dogs had echocardiographic abnormalities, but changes were more severe in group-2 than in group-1 dogs. Ventricular tachyarrhythmias were documented in all dogs. Group-1 dogs were more likely to have episodes of sustained ventricular tachycardia than were group-2 dogs. Multifocal interstitial fibrosis and replacement of muscle fibers with collagen and fat were consistently observed in hearts from dogs that died suddenly. Ten group-1 dogs had received antiarrhythmic treatment prior to death. CLINICAL IMPLICATIONS: Occult cardiomyopathy can be identified by means of echocardiography and Holter monitoring in Doberman Pinschers. Doberman Pinschers with cardiomyopathy that had episodes of sustained (> 30 seconds) ventricular tachycardia were at risk of dying suddenly.

Animals↗
PubMed1997

A team approach to the environment of care.

The author provides a step-by-step description of how his hospital used the team approach to comply with the Environment of Care standards of JCAHO. The end result--a high score with commendation--justifies the means, he says.

Health Facility Environment↗
PubMed1997

Pharmacokinetics of propranolol in healthy cats during euthyroid and hyperthyroid states.

OBJECTIVE: To examine the pharmacokinetic profile of propranolol in cats before and during experimentally induced hyperthyroidism. ANIMALS: 8 conditioned, random-source, young adult, female cats. PROCEDURE: Propranolol was administered i.v. as a single bolus and 72 hours later by mouth. Thereafter, the cats were dosed for 5 weeks with L-thyroxine (50 micrograms/kg of body weight, s.c., once daily) to induce hyperthyroidism (serum thyroxine concentration, 217 +/- 17 nmol/L). Blood samples were obtained at appropriate intervals before and during hyperthyroidism and were analyzed for plasma propranolol concentration by use of high-performance liquid chromatography. RESULTS: In all cats, a two-compartment model best described the control and hyperthyroid intravenous data. The change in thyroid status from euthyroid to hyperthyroid caused a significant (P < 0.05), but small reduction in propranolol area under the curve (19,932 +/- 7,900 min.micrograms/L vs 15,911 +/- 1,400 min.micrograms/L) after i.v. administration. In contrast, after oral administration during the hyperthyroid state, a twofold increase (P < 0.05) in propranolol area under the curve (105,430 +/- 57,600 min.micrograms/L vs 226,811 +/- 112,000 min.micrograms/L) and peak serum propranolol concentration (651 +/- 247 micrograms/L vs 1191 +/- 590 micrograms/L) were attributed to significant (P < 0.05) increase in propranolol bioavailability caused by increased fractional absorption (57 +/- 28% vs 137 +/- 73%) and decreased total body clearance (58 +/- 27 ml/min/kg vs 30 +/- 19 ml/min/kg). Mean arrival time after oral dosing was significantly lengthened by hyperthyroidism (100 +/- 38 minutes vs 157 +/- 71 minutes). CLINICAL RELEVANCE: Hyperthyroidism-induced changes in propranolol pharmacokinetics may signal the need to reduce doses of propranolol when they are orally administered to hyperthyroid cats.

Administration, Oral↗
PubMed1996

Cure of disseminated xenografted human Hodgkin's tumors by bispecific monoclonal antibodies and human T cells: the role of human T-cell subsets in a preclinical model.

Cure of a single established human Hodgkin's tumor growing subcutaneously in severe combined immunodeficient (SCID) mice can be achieved with a complex protocol using two bispecific monoclonal antibodies (Bi-MoAb) directed against the Hodgkin's associated CD30 antigen and the T-cell triggering molecules CD3 and CD28, respectively, together with human T cells prestimulated in vitro with Bi-MoAbs in the presence of CD30+ cells. To adapt this model to the clinical situation, disseminated tumors were established in SCID mice by intravenous injection of 2 x 10(7) cells of the Hodgkin's derived cell line L540CY. Treatment of SCID mice bearing disseminated CD30+ Hodgkin's tumors with the combination of CD3/CD30 and CD28/CD30 Bi-MoAbs and naive (ie, not in vitro prestimulated) human T cells resulted in the cure of all appropriately treated animals. T lymphocytes obtained from patients with advanced stage untreated Hodgkin's disease were as effective as lymphocytes from healthy controls. Treatment was effective even when delayed until 2 weeks after tumor inoculation, and application of Bi-MoAbs into SCID mice with circulating human T cells was as effective as injecting the Bi-MoAbs before the lymphocytes. Treatment results with isolated CD4+ and CD8+ human T cells suggest that both subsets are necessary for the Bi-MoAb mediated cure of xenografted human tumors in vivo. The efficacy and practicability of this preclinical immunotherapy protocol support and form the basis for the clinical evaluation of this approach in patients with Hodgkin's disease resistant to standard therapy.

Animals↗
PubMed1996

Wolbachia: intracellular manipulators of mite reproduction.

Cytoplasmically transmitted Wolbachia (alpha-Proteobacteria) are a group of closely related intracellular microorganisms that alter reproduction in arthropods. They are found in a few isopods and are widespread in insects. Wolbachia are implicated as the cause of parthenogenesis in parasitic wasps, feminization in isopods and reproductive (cytoplasmic) incompatibility in many insects. Here we report on the widespread occurrence of Wolbachia in spider mites and predatory mites based on a PCR assay for a 730 bp fragment of the ftsZ gene with primers that are specific for Wolbachia. An additional PCR, using two primer pairs that amplify a 259 bp region of the ftsZ gene that are diagnostic for the two Wolbachia subdivisions A and B, showed that infected mites only carried type B and not type A Wolbachia. The fact that some species tested negative for Wolbachia does not mean that the entire species is uninfected. We found that natural populations of Tetranychus urticae are polymorphic for the infection. The possible effects of Wolbachia on mite reproduction and post-zygotic reproductive isolation are discussed.

Animals↗
PubMed1996

N-ras genes are not mutated in Hodgkin and Reed-Sternberg cells: results from single cell polymerase chain-reaction examinations.

Ras mutations play an important role in many human tumors. They usually occur at only three codons (12, 13 and 61) of the three ras gene family members and lead to altered proteins resulting in a constitutively activated downstream signal cascade. We have examined the N-ras gene status in Hodgkin's disease (HD). Little is known about the pathogenetic events leading to malignant phenotype in HD. Since Hodgkin and Reed-Sternberg (H and RD) cells comprise only a minority of the cellular infiltrate in HD-lymph nodes, molecular studies concerning the status of oncogenes have been difficult to perform and have yielded conflicting results. We have established a single cell PCR assay for N-ras analysis and have examined H and RS cells from 12 cases of HD by PCR amplification and direct sequencing. None of the single H and RS cells examined carried N-ras mutations at either codons 12/13 or 61. Therefore, N-ras mutations are not involved in the pathogenesis of HD.

Adult↗
PubMed1996

Laparoscopic liver biopsy to evaluate hepatic dysfunction in patients with hematologic malignancies: a useful tool to effect changes in management.

Hepatic dysfunction is common in patients who receive intensive chemotherapy and it is important to determine the etiology in order to institute appropriate therapy. The role of laparoscopic liver biopsy in patients with neutropenia, thrombocytopenia, or both was evaluated as a mean of making treatment decisions and as a determinant of clinical outcome. Laparoscopic liver biopsy was performed in 29 subjects who were receiving intensive cytotoxic therapy with or without bone marrow transplantation. One to three direct-vision laparoscopic liver biopsies were performed in each patient using a Tru-cut needle during general anesthesia. Platelet concentrate transfusions were usually given before, during, and immediately after biopsy. Bleeding was controlled with spatula electrocautery. Thirty-two biopsies were obtained in 29 patients. At the time of liver biopsy, white blood cell and platelet counts ranged from 0 to 14,300/microliters (median: 2500/microliters), and 1000 to 47,000/microliters (median: 20,000/microliters), respectively. Bleeding at the liver biopsy site was readily controlled during the procedure without clinical evidence of significant bleeding; no procedure-related complications were noted and no patients required re-exploration. All biopsies were informative and the lesions observed in 32 biopsies revealed graft-versus-host disease (n = 5), hepatic candidiasis (n =1), hepatic veno-occlusive disease (n = 3), cholestasis (n = 19), hemosiderosis (n = 26), toxic injury (n = 8), hepatic steatosis (n = 4), granuloma (n = 1), viral infection (n =1), and malignancy (n = 1). Laparoscopic liver biopsy has been proven to be an effective means of assessing the cause of liver dysfunction in patients who were thrombocytopenic and immunosuppressed. The diagnosis obtained at laparoscopic liver biopsy altered therapy in nine of 29 (31%) patients.

Adult↗
PubMed1995

[Ki-ras mutation as a molecular tumor marker for carcinoma of the pancreas].

More than 90% of tumours of the pancreas have mutations on codon 12 of the Ki-ras oncogene. Cellular DNA from pancreatic secretions and fine-needle biopsies, obtained from 69 patients (41 men, 28 women), were amplified by the polymerase chain reaction (PCR) to demonstrate this characteristic marker. All these patients had undergone endoscopic retrograde pancreatography for suspected pancreatitis or carcinoma of the pancreas. Two different methods were developed to demonstrate the mutations. With the aid of one of these methods, enrichment PCR with analysis of the restriction fragment length (FL), mutations on codon 12 of the Ki-ras gene were demonstrated in unstimulated pancreatic secretions of 29 of 33 patients with pancreatic carcinoma. All eleven fine-needle biopsies that had been cytologically examined showed the tumour-specific mutation. After direct sequencing of enrichment PCR a codon 12 mutation was demonstrated in pancreatic secretion from 21 of 24 patients and with the single strand conformation polymorphism analysis in 17 of 33 patients. In two of these 33 patients two different Ki-ras mutations were discovered. No mutations were found in acute inflammations or stone disease, while in five patients with chronic pancreatitis mutations were demonstrated only in those two patients in whom histological examination had revealed precancerous mucinous hyperplasia. This investigation indicates that codon 12 mutations of the Ki-ras gene, found after PCR in pancreatic secretion and biopsies, constitute a sensitive and specific tumour marker whose clinical value is being assessed.

Biomarkers, Tumor↗
PubMed1995

The B lymphocyte in rheumatoid arthritis: analysis of rearranged V kappa genes from B cells infiltrating the synovial membrane.

The participation of the humoral immune system in rheumatoid arthritis (RA) is characterized by the production of rheumatoid factors (RF). RF are autoantibodies against the Fc part of IgG which are encoded by diverse germ-line genes. Most of the RF-encoding genes are unmutated, but in RA, a substantial quantity is encoded by somatically mutated genes. In addition, the synovial membranes (SM) of the diseased joints of RA patients are infiltrated by B lymphocytes which form germinal center-like aggregates. To analyze the local immune response, B cell foci from two RA SM were isolated by micromanipulation. From DNA of these foci, the rearranged kappa light chain variable region (V kappa) genes were amplified by polymerase chain reaction (PCR), cloned and sequenced. The amplification of different V kappa-J kappa combinations of different foci suggested oligoclonal expansion of B lymphocytes, which was confirmed by sequence analysis: each PCR product contained members of a single B cell clone. The sequence analysis of 29 different clones revealed rearrangements of diverse V kappa genes. Both frequent representatives of the V kappa 3 and the V kappa 1 family, as well as rarely used genes such as the L10 and B2 genes of the V kappa 2 and V kappa 5 families were found. Of the eleven potentially functional gene rearrangements, eight were significantly mutated, indicating their derivation from antigen-selected B cells. Intraclonal diversity in one of these clones may suggest ongoing mutation in the diseased synovial membrane of patients with RA.

Adult↗
PubMed1995

Acute cholecystitis after autologous bone marrow transplantation for acute myeloid leukemia.

BACKGROUND: We investigated the incidence of acute cholecystitis in patients with acute myeloid leukemia (AML) undergoing autologous bone marrow transplantation in complete remission. PATIENTS AND METHODS: Thirty-five consecutive acute myeloid leukemia patients were given oral busulfan 4 mg/kg/day for 4 days and IV cyclophosphamide 50 mg/kg/day for 4 days followed by reinfusion of autologous bone marrow purged with 4-hydroperoxycyclophosphamide. RESULTS: Five of 35 patients developed clinical evidence of acute cholecystitis, manifested by fever, nausea, vomiting, right-upper-quadrant pain, and abdominal guarding, within 18 days after autologous bone marrow infusion. Ultrasonography and CT scans of the abdomen supported the diagnosis of cholecystitis. Three patients underwent cholecystectomy, while two patients were treated medically; all recovered uneventfully. A review of 338 consecutive bone marrow transplant patients who underwent marrow transplantation for a variety of diseases and were treated with other high-dose cytotoxic regimens during the same time period revealed significantly fewer cases of cholecystitis, i.e. two, (p < 0.0001). CONCLUSIONS: Five of 35 AML patients undergoing autologous bone marrow transplant using busulfan, cyclophosphamide, and purged bone marrow developed evidence of acute cholecystitis. These findings suggest that the busulfan/cyclophosphamide preparative regimen may be associated with acute cholecystitis. The true incidence of this injury and its pathogenesis remain to be elucidated.

Acute Disease↗
PubMed1994

Combining lithium and sodium valproate for bipolar disorder.

We report two cases of severe bipolar disorder in which there was a dramatic response to the combination of lithium and sodium valproate. Both patients had failed to respond to the respective monotherapies. These cases suggest that the combination of lithium and sodium valproate may be more effective than each of these drugs used alone. There is a clear need for controlled outcome studies of the common clinical practice of combining lithium and the anticonvulsants.

Bipolar Disorder↗
PubMed1994

Hepatic dysfunction in patients with carcinoma who are severely thrombocytopenic and immunosuppressed.

BACKGROUND: The use of intensive cytotoxic drug therapy for malignant disorders often results in hepatic dysfunction. It is important to determine the cause of hepatic injury to institute appropriate therapy; however, neutropenia and thrombocytopenia may prevent performance of hepatic biopsy to establish a cause. STUDY DESIGN: We prospectively evaluated the cause of hepatic dysfunction using laparoscopic biopsy of the liver in 20 consecutive patients who were receiving intensive cytotoxic therapy, with or without bone marrow transplantation, or who were being treated for severe aplastic anemia. One to three direct-vision laparoscopic biopsies were performed in each patient during general anesthesia and bleeding was controlled with spatula electrocautery. Platelet concentrate transfusions were given before, during, and immediately after the biopsy. RESULTS: Platelet and leukocyte counts at the time of hepatic biopsy ranged from 1,000 to 83,000 per microL (median of 23,500 per microL) and zero to 14,300 per microL (median of 2,200 per microL), respectively. Nineteen of 20 patients had platelet counts of less than 68,000 per microL. Bleeding at biopsy site was controlled during the procedure without evidence of bleeding or complications after biopsy. Biopsy specimens revealed graft-versus-host disease (n = 2), hepatic veno-occlusive disease (n = 1), steatosis (n = 5), cholestasis (n = 19), hemosiderosis (n = 19), and granuloma (n = 1). CONCLUSIONS: In several patients, the knowledge derived from hepatic biopsy results altered the therapeutic strategy. The use of laparoscopic hepatic biopsy to assess the cause of hepatic dysfunction should be encouraged because it is a safe procedure, even in patients who are severely thrombocytopenic and immunocompromised.

Adolescent↗
PubMed1993

Merkel cell carcinoma of the vulva.

We present the clinical, histopathologic, and ultrastructural features of a primary vulvar Merkel cell carcinoma. This tumor appears to have a more aggressive behavior than those at other anatomic sites. A review of reported cases is presented. Preoperative evaluation and the role of surgery, radiotherapy, and chemotherapy in the management of these tumors are discussed.

Carcinoma, Merkel Cell↗
PubMed1993

Terminal hepatic failure in erythropoietic protoporphyria.

Erythropoietic protoporphyria is an inherited disorder characterized biochemically by a deficiency of ferrochelatase, the enzyme that catalyzes the incorporation of ferrous iron into protoporphyrin to form heme. We describe a patient who illustrates the unpredictability of the course of liver disease in erythropoietic protoporphyria. She remained stable for several years after her first evidence of liver function abnormalities. Then, in a period of weeks, hepatic failure developed and she died. Findings of serial liver biopsy specimens showed extensive hepatocellular degeneration and inflammation that appeared in a 10-day period. The factors that cause this rapid deterioration in hepatic function remain unknown. Reported cases of fatal hepatic failure in patients with erythropoietic protoporphyria are reviewed.

Aspartate Aminotransferases↗
PubMed1993

[Deinstitutionalization of chronic psychiatric patients exemplified by a public psychiatric hospital].

Basing on the multifarious phenomena of hospitalism in chronically mentally ill patients the authors report on a survey of known facts and analyses to enable focussing of appropriate on-target measures were taken to arrive at conclusions for caring for these long-term patients: 1. Fixing the deadline of the study; 2. Determining the quality of patient care; 3. Analysing the experiences collected in respect of the integrated training programme to promote cognitive, communicative and social abilities and skills among the patients in resident living quarters within the confines of the hospital. An attempt is made to arrive at an overall evaluation of the measures taken so far in respect of de-hospitalisation and in building up complementary settlements outside the hospital but close to communal institutions.

Adult↗