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Biomedical subjects

J Baker

Publications and source records attributed to J Baker.

At least 235 records · Page 13Linked to original sources
PubMed1988

Neuroendocrine carcinomas of the colon and rectum: a clinicopathologic evaluation.

Neuroendocrine carcinomas were diagnosed in 13 of 683 patients who had colon cancers removed from January 1980 to June 1987 for an incidence of 1.9%. The patients were 28 to 89 years of age (median, 72 years). There were seven male and six female patients. The treatment was as follows: right hemicolectomy, 5; transverse colectomy, 1; left hemicolectomy, 1; low anterior resection, 2; abdominal-perineal resection, 1; and in 3 patients with rectal tumors, biopsy examination only was performed. Microscopic stages were as follows: Dukes' stage B, 1; stage C, 6; stage D, 5; and stage indeterminate, 1. By light microscopy, the tumors showed solid clusters or ribbons of round to fusiform, small to intermediate-sized cells with variably abundant mitoses. Eight tumors had foci of glandular and/or squamous differentiation. By immunohistochemistry, all tumors showed one or more neuroendocrine markers, including neuron-specific enolase, chromogranin, synaptophysin, serotonin, and various neuropeptides. By electron microscopy, single membrane-bound neurosecretory granules were noted. The sites of metastases included regional nodes, 8; liver, 5; bone, 1. Four patients were treated with a combination of chemotherapy and radiation therapy. These tumors were, as a group, aggressive, with eight patients dead within 12 months of diagnosis. Median survival was 7 months, with three patients alive at 2, 38, and 68 months, respectively. Specifically, small- and intermediate-cell neuroendocrine carcinomas of the colon and rectum behaved very aggressively and displayed numerous structural and functional similarities with their bronchopulmonary counterparts.

Adult↗
PubMed1988

Hemorrhagic shock-induced bacterial translocation is reduced by xanthine oxidase inhibition or inactivation.

Experiments were performed to determine whether bacterial translocation (BT) after hemorrhagic shock is due to a reperfusion injury mediated by xanthine oxidase-derived oxidants. Rats were subjected to 30 minutes of shock (30 mm Hg) followed by reinfusion of shed blood. Twenty-four hours after hemorrhage and reinfusion, the mesenteric lymph node, liver, and spleen were harvested from each animal for bacterial culture, and the ileum and cecum were examined histologically. Sham-shocked (control) rats were instrumented, but blood was not withdrawn. The incidence of BT was higher in the shocked rats (61%) than in the sham-shocked animals (7%) (p less than 0.01). Allopurinol (50 mg/kg, administered orally), a competitive inhibitor of xanthine oxidase, reduced the incidence of shock-induced BT to 14% (p = 0.02). Similarly, rats fed a tungsten-supplemented molybdenum-free diet, which inactivates xanthine oxidase, reduced shock-induced BT to 10% (p = 0.02). The histologic damage cause by hemorrhagic shock was prevented by blocking xanthine oxidase activity. Thus hemorrhagic shock-induced bacterial translocation from the gut appears to be mediated by oxidants generated by activation of the xanthine oxidase system.

Allopurinol↗
PubMed1987

Fructosamine in a diabetic clinic.

Serum fructosamine concentrations were measured in 660 adults attending the diabetic clinic at Auckland Hospital over a 12 month period. Only 44 (6.6%) patients had results within the physiological range whereas 237 (35.9%) patients had values greater than 3.7 mmol/l consistent with poor blood glucose control. Moreover, patients with elevated frustosamine values had a much higher frequency of retinopathy than the normal fructosamine group. When frustosamine values were compared with physician's assessment of control and with random glucose results, we found weak correlations suggesting that poor control in many patients was not previously recognised. We conclude that fructosamine measurement in a diabetic clinic provides important clinical information complementing traditional assessments of metabolic control.

Adolescent↗
PubMed1987

Tick-bite fever in pregnancy. A case report.

Despite the frequency of tick-bite fever in southern Africa and its doubtless occurrence in pregnancy, this report documents the first case in a pregnant woman. Consequently, the natural history of tick-bite fever in pregnancy and concomitant placental involvement must be regarded as conjectural. Accordingly a register has been opened by the Department of Obstetrics and Gynaecology, University of the Witwatersrand, for recording similar cases. At this stage of our knowledge, erythromycin 500 mg 6-hourly until 3-5 days after defervescence is the therapy of choice for such patients.

Adult↗
PubMed1987

Dependence of cat vestibulo-ocular reflex direction adaptation on animal orientation during adaptation and rotation in darkness.

Four series of experiments investigated how adaptive changes in direction of the cat's vestibulo-ocular reflex (VOR) vary with position of the animal during adaptive training and postadaptive testing. In all experiments VOR was measured electrooculographically during rotations about earth-horizontal and vertical axes in the dark before and after 2 h of adaptation in which 0.25 Hz sinusoidal whole body rotation about a horizontal/vertical axis was paired with synchronous 0.25 Hz rotation of a visual pattern about a vertical/horizontal axis, respectively. In upright sagittal (US) experiments, coupling of pitch rotation with visual pattern rotation about an earth vertical axis yielded an adaptive horizontal VOR response to pitch rotation whose gain had a local maximum at 0.25-0.5 Hz plus a sustained rise for frequencies below 0.1 Hz. When post-tests were done with the animal rolled 90 degrees onto its side and rotated about the earth vertical axis (pitch relative to the cat), the low frequency rise was eliminated and the 0.25 Hz peak was reduced. In on side sagittal (SS) experiments, where training was done in the latter (on side) position, training produced only the 0.25 Hz peak without the low frequency rise, indicating that the rise is due to coupling of otolith input to horizontal VOR. Again the 0.25 Hz peak was reduced when testing was done with the cat oriented 90 degrees from the training position (in the US position). This indicates that the cross-coupled canal-ocular reflex response is modulated or gated by the position of the animal with respect to gravity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Ocular↗
PubMed1987

Bone scanning in pregnant patients with breast carcinoma.

Radionuclide scanning is usually contraindicated in pregnancy because of the danger of fetal radiation exposure. Radionuclide bone scanning with Tc-99m MDP is a sensitive indicator of early osseous metastases in breast cancer. Three cases of breast cancer during pregnancy are reported; modified bone scanning was utilized for staging and decision analysis. Modifications of bone scanning techniques to minimize fetal radiation exposure and fetal dosimetry calculations are described.

Abdomen↗
PubMed1987

Serum fructosamine as a screening method for diabetes mellitus in patients with suspected acute myocardial infarction.

It is important to identify diabetic patients in a coronary care population because they have a higher risk of suffering congestive heart failure, dysrhythmias and death following myocardial infarction. In order to determine the most efficient screening method for diabetes, we compared fructosamine and glucose measurements on admission blood specimens from 256 consecutive patients. Of 15 (5.9%) known diabetic patients, 12 had glucose results greater than or equal to 7.8 mmol/l and nine had fructosamine levels greater than 2.87 mmol/l. However, elevated glucose results were also found in a high proportion (49.2%) of patients with no previous history of diabetes. We performed glucose tolerance tests in 107 patients after discharge to determine the frequency of false-positive observations. Fructosamine yielded five (4.6%) false-positive results, whereas plasma glucose yielded 47 (43.9%) false-positive observations. We conclude that serum fructosamine provides a more specific screening method for diabetes in this population because the results are unaffected by stress hyperglycemia.

Adult↗
PubMed1987

Preliminary observations on a second Mr approximately equal to 24,000 membrane molecule from rat spermatozoa.

Preliminary data are presented to show that the integral membrane glycoprotein found on rat cauda epididymal spermatozoa is one of two Mr = approximately 24,000 molecules that are associated with sperm membranes. The second molecule can be differentiated from the glycoprotein by a variety of antibodies and can be shown to be present in spermatozoa and in residual bodies present in the epididymal fluid. The second molecule can be localized immunocytochemically in spermatids and Leydig cells in the testis.

Cell Membrane↗
PubMed1987

Temporal changes in effectiveness of an inspiratory inhibitory electrical pontine stimulus.

We determined the temporal changes in effectiveness of inspiratory-shortening expiratory-prolonging stimulus trains delivered in the region of the nucleus parabrachialis medialis and compared the responses to those observed during trains delivered to the vagus in the same animals (pentobarbital, sodium-anesthetized paralyzed cats). The inspiratory inhibitory effect of the pontine stimulus was assessed from the effect the stimulus has on threshold for terminating inspiration. Stimulus effect increased gradually, reached a peak at 0.2-0.4 s, and declined thereafter. The time of occurrence of peak effect was different from that observed in the course of vagal stimulus trains. With long stimulus trains (19-40 s), the initial effect on inspiratory duration (TI) (i.e., shortening) rapidly subsided and, in six of eight animals, was replaced by TI prolongation. The initial effect on expiratory duration (TE) (i.e., prolongation) also gradually declined with time but TE remained above control throughout. The time constant of adaptation was very similar with vagal and pontine stimulus trains (12.2 and 11.0 s, respectively), but the gain of the adapting response was much more pronounced with pontine stimuli, resulting in a paradoxical effect while stimulation continued. We conclude that the response to pontine stimuli, as with vagal stimuli, displays both integrative and adaptive characteristics. The similarity of the time constants for vagal and pontine adaptation responses suggests that these two inputs share common processing pathways.

Animals↗
PubMed1986

Dynamics of adaptive change in vestibulo-ocular reflex direction. II. Sagittal plane rotations.

Alert cats were rotated sinusoidally (0.25 Hz) in their sagittal plane while viewing optokinetic motion in their horizontal plane. Vertical and horizontal vestibulo-ocular reflex (VOR) was measured in the dark before and after 2 h of these adaptation stimuli in upright or onside orientation of the cat. Onside exposure produced maximal adaptive horizontal VOR at the training frequency. Upright exposure produced highest gain at lower frequencies. A cat with inoperative vertical canals adapted only to upright exposure. We conclude that in the presence of horizontal image rotation either vertical canal or otolith stimulation can produce adaptation in VOR direction and stimulation of both produces complex adaptation dynamics.

Adaptation, Physiological↗
PubMed1986

Intraoperative autotransfusion in urologic oncology.

The value of autotransfusion is widely recognized in the surgical community and may be of increasing importance in prevention of acquired immunodeficiency syndrome and hepatitis. The concern of potential contamination of the blood with viable tumor cells has resulted in limited use of autotransfusion in cancer surgery. The objective of this study was to examine the benefits and safety of autotransfusion in patients undergoing major surgery of genitourinary tumors. Autotransfusion was used in 49 consecutive patients. Twenty-four patients had radical cystectomy, ten had radical prostatectomy, 13 had radical nephrectomy, and two had other types of operations. An autotransfusion machine (Haemonetics Cell Saver) was used. The follow-up included physical examination, chest roentgenogram every three months, and bone scan and computed tomographic scan if clinically indicated. Liver and renal profiles were routinely performed every three months. Five of 49 patients developed metastases during follow-up examination from 12 to 23 months. The low incidence of metastatic spread and the pattern of spread fall to implicate autotransfusion as a cause of tumor dissemination. Autotransfusion and predeposited blood banking may result in elimination of or significant reduction in homologous transfusions.

Adult↗
PubMed1986

Characterization of a variant prekallikrein, prekallikrein Long Beach, from a family with mixed cross-reacting material-positive and cross-reacting material-negative prekallikrein deficiency.

Studies of plasma prekallikrein in a family with prekallikrein deficiency were made. Three children had no clotting activity but approximately 35% antigen levels, and the mother and five children had twice as much prekallikrein antigen as clotting activity, suggesting the presence of a dysfunctional molecule. A nonfunctional variant form of prekallikrein was purified that contained no prekallikrein clotting activity. The variant and normal molecules were both 80,000 mol wt, immunologically indistinguishable and complexed similarly with high molecular weight kininogen. Isoelectric focusing studies suggested a difference of one charged amino acid residue. The variant was cleaved by beta-Factor XIIa 200 times slower than the normal molecule, and no amidolytic activity was detected for the cleaved variant. These data and other observations suggest that an amino acid was substituted in the variant near the NH2-terminal end of the kallikrein light chain resulting in slower cleavage by beta-Factor XIIa and the absence of enzymatic activity.

Adult↗
PubMed1986

A prospective randomized trial comparing high-dose cisplatin with low-dose cisplatin and chlorambucil in advanced ovarian carcinoma.

Sixty-one patients with FIGO stage III ovarian carcinoma and 30 patients with stage IV ovarian carcinoma were randomized to receive either high-dose cisplatin (100 mg/m2) or low-dose cisplatin (20 mg/m2) and chlorambucil. Overall response rates were similar in both arms, with 68% and 49% of stage III patients and 61% and 72% of stage IV patients responding to high-dose cisplatin and the combination, respectively. There was a strong trend for better survival in stage III (P less than .05) but not in stage IV patients treated with cisplatin alone. The toxicity suffered by patients treated with high-dose cisplatin was severe, and in 15 patients cisplatin therapy was stopped because of unacceptable toxicity.

Actuarial Analysis↗
PubMed1986

Quality assessment of determinations of serum fructosamine in 33 clinical chemistry laboratories.

We investigated the analytical performance of fructosamine measurement in 33 routine clinical chemistry laboratories. We prepared 12 human control sera spanning a range of nondiabetic and diabetic fructosamine concentrations and assigned target values by using commercial reagents and a Cobas Bio centrifugal analyzer. Each control serum was analyzed by participating laboratories on two separate occasions. Averaged results were compared with target values, and systematic error was determined from slope and intercept regression coefficients. Overall, we found no significant (p greater than 0.05) slope or intercept bias, although slight nonlinearity was found with bichromatic instruments. Random error was determined from the standard error of estimate and from duplicate measurements. We found a median interlaboratory CV of 5.36% and similar analytical performance with all automated instruments used. The median random error with manual techniques was 18.1%. We conclude that fructosamine measurement as currently performed in routine laboratories is sufficiently accurate and reliable to function as an index of blood glucose control in diabetic patients.

Blood Glucose↗
PubMed1985

Presenting conditions of 1539 population-based lung cancer patients by cell type and stage in New Hampshire and Vermont.

The authors identified all newly diagnosed lung cancer cases in New Hampshire and Vermont for the period 1973 through 1976 and abstracted clinical data on presenting symptoms and findings from their hospital records. Microscopy slides were also reviewed, when possible, to confirm cell type. The most frequent presenting symptoms were weight loss (46%) and cough (45%). Other common symptoms were dyspnea (37%), weakness (34%), chest pain (27%), and hemoptysis (27%). The presence of symptoms and findings was in general related to disease stage but bore little relationship to cell type. These results differ from those of previously reported case series that were based on surgical, radiation therapy, or Veterans Hospital groups, but the current data agree closely with those from another population-based series in Finland.

Adenocarcinoma↗
PubMed1985

Serum fructosamine in patients with diabetes mellitus.

Serum fructosamine was compared with other measures of blood glucose control in 11 non-diabetic volunteers, 14 type 1 and 14 type 2 diabetic patients. Estimates of mean plasma glucose concentrations for the 28 diabetic patients were made by nine physicians, based on their interpretation of historical data, home capillary blood glucose profiles, fasting and random plasma glucose and plasma lipid levels. Significant differences between estimated and measured mean glucose levels were apparent with a tendency for physicians to underestimate mean blood glucose in the hyperglycaemic range (glucose greater than 11 mmol/l). Fructosamine results on the same patients correlated linearly both with mean plasma glucose concentrations (r = 0.86, p less than 0.001) and with glycosylated haemoglobin (HbA1c) levels (r = 0.93, p less than 0.001) and correctly classified diabetes control in most patients. Despite marked fluctuations of plasma glucose concentration, serum fructosamine levels measured at different times of the day did not alter significantly. We conclude that a random serum sample analysed for fructosamine provides a simple and reliable means to measure the efficacy of therapy and often provides information superior to clinical assessment of diabetic control.

Adolescent↗