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Biomedical subjects

H Hoffman

Publications and source records attributed to H Hoffman.

At least 19 recordsLinked to original sources
PubMed1991

Drug response of head and neck tumors in native-state histoculture.

We describe a chemosensitivity testing of head and neck tumors, in which a native-state histoculture, ie, a three-dimensional culture system that maintains important in vivo properties, including tissue architecture, was used. Fifteen specimens of head and neck tumors were evaluated for sensitivity to the following drugs: cisplatin (DDP) at concentrations of 1.5, 15, and 37.5 micrograms/mL; fluorouracil at concentrations of 4.0, 40, and 100 micrograms/mL; and combinations of cisplatin and fluorouracil in corresponding doses. Growth and measurement of drug responses were successfully completed in 10 specimens (five others were contaminated, four of them prior to instituting rigorous antibiotic washes). The results indicated cisplatin sensitivity in five of 10 patients; fluorouracil sensitivity in four of 10 patients; and fluorouracil-cisplatin sensitivity in seven of eight patients. Our preliminary results indicate that the native-state histoculture technique is feasible to test chemosensitivity of head and neck tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Automatic processes in word perception: an analysis from illusory conjunctions.

When asked to report the color of a target letter in a briefly presented word or pseudoword, Ss were more likely to report the color of letters from the same syllablelike unit than the color of other letters. Because Ss were not required to make a lexical decision or naming response, the multiletter units that are revealed by this task arise automatically. It was found that the syllablelike units are not phonological but correspond to orthographic patterns and morphemes. These units affect performance regardless of changes in letter-case, suggesting that the units are based on abstract letter identities. Unit formation was also not affected by visual field of presentation. Several experiments demonstrated that the morphological and orthographic units arise from different processes: The morphological units depend on lexical access, and the orthographic units do not. Finally, the effects of orthography are stronger for good readers than for poor readers.

Adolescent↗
PubMed1991

Eye fixations and memory for emotional events.

Subjects watched either an emotional, neutral, or unusual sequence of slides containing 1 critical slide in the middle. Experiments 1 and 2 allowed only a single eye fixation on the critical slide by presenting it for 180 ms (Experiment 1) or 150 ms (Experiment 2). Despite this constraint, memory for a central detail was better for the emotional condition. In Experiment 3, subjects were allowed 2.70 s to view the critical slide while their eye movements were monitored. When subjects who had devoted the same number of fixations were compared, memory for the central detail of the emotional slide was again better. The results suggest that enhanced memory for detail information of an emotional event does not occur solely because more attention is devoted to the emotional information.

Adult↗
PubMed1990

Risk of neural tube defects in relation to maternal fertility and fertility drug use.

In a case-control study to investigate whether women who use drugs to induce ovulation are at increased risk of conception of a child with a neural tube defect, 571 women who had a fetus or child with a neural tube defect, 546 women who had a fetus or child with other abnormalities, and 573 women who had an apparently normal fetus or child were questioned about infertility, fertility drug use, and related obstetric problems. The rate of maternal fertility drug use around the time of conception was not significantly higher for neural tube defects than for other abnormalities (odds ratio 1.28; 95% confidence interval 0.39, 4.51) or no abnormalities (odds ratio 0.80; 95% Cl 0.27, 2.27). Fertility drug use at any time was not significantly more frequent for neural tube defects than for other abnormalities (odds ratio 1.37; 95% Cl 0.70, 2.74) or no abnormalities (odds ratio 1.05; 95% Cl 0.56, 1.98).

Abnormalities, Drug-Induced↗
PubMed1990

Decreased L system amino acid transport and decreased gamma-glutamyl transpeptidase are independent processes in human chronic lymphocytic leukemia B-lymphocytes.

The L system of amino acid transport is markedly diminished in chronic lymphocytic leukemia (CLL) B-lymphocytes, with a maximal velocity less than 15% that of normal B-lymphocytes. Another membrane-associated function, the activity of the ectoenzyme, gamma-glutamyl transpeptidase (GGT), is diminished in CLL B-cells to 30% that of normal B-cells. In addition to its transpeptidase activity, a role for GGT has been postulated in the transport of amino acids. In the present report, the possible relationship of these two physiologic functions CLL B-cells was studied. The L system transport defect in CLL is restored by phorbol ester-induced cell maturation; following incubation with 0.15 microM tetradecanoyl phorbol acetate (TPA) for 17 hours, the L system initial velocity showed a 20-fold increase. In contrast, there was no significant effect on GGT activity with cell maturation. Furthermore, an antibody which diminished GGT activity by 50% in lymphoid cells did not inhibit L system transport. Thus, the impaired L system amino acid transport and GGT activity appear to be independent processes in CLL B-cells.

Amino Acids↗
PubMed1990

Prevalence of seasonal affective disorder at four latitudes.

The Seasonal Pattern Assessment Questionnaire (SPAQ) was mailed to a sample population balanced for sex and randomly selected from local telephone directories in four areas: Nashua, NH, New York, NY, Montgomery County, MD, and Sarasota, FL. On the basis of responses to this questionnaire, prevalence rates of winter seasonal affective disorder (winter SAD), summer seasonal affective disorder (summer SAD), and subsyndromal winter SAD were estimated for the four areas. Rates of winter SAD and subsyndromal SAD were found to be significantly higher at the more northern latitudes, while no correlation was found between latitude and summer SAD. The positive correlation between latitude and prevalence of winter SAD applied predominantly to the age groups over 35.

Adult↗
PubMed1990

Pineal region germinomas in childhood treatment considerations.

From 1967-1986, 21 children were treated for pineal germinoma, including 16 biopsy-proven, 2 biopsy non-diagnostic, and 3 metastatic unbiopsied (marker negative) patients. Ten of 18 (56%) biopsied patients underwent partial or sub-total tumor resection. Twenty patients were irradiated, 19 of whom are alive. No irradiated patient died of progressive germinoma, but two patients relapsed in the spinal cord and required treatment intensification for salvage. Long-term survivors have significant morbidity. Determination of the minimum effective treatment remains the chief therapeutic challenge.

Adolescent↗
PubMed1990

Posterior fossa medulloblastoma in childhood: treatment results and a proposal for a new staging system.

Seventy-two children with posterior fossa medulloblastoma were diagnosed at the Hospital for Sick Children, Toronto, from 1977 to 1987 and treated by standard methods. The 5- and 10-year survival and disease-free survival rates were 71% and 63%, and 64% and 63%, respectively. Total tumor resection, as determined by the surgeon was the most significant favorable prognostic factor. Post-operative meningitis, a residual enhancing mass lesion on the post-operative, pre irradiation CT scan and dissemination to the brain or cord at diagnosis were unfavorable factors. These four easily definable factors were used to define a staging system with prognostic significance. Five-year disease-free survival rates were for Stage I (total resection, no adverse factor) 100%, Stage II (total resection with one or more adverse factor or less than total resection with no other adverse factor) 78%, and Stage III (less than total resection with one or more adverse factor) 18%. Evaluation of treatment results in medulloblastoma requires that these prognostic factors be known.

Adolescent↗
PubMed1990

Delayed and progressive multiple suture craniosynostosis.

A considerable amount of information is available on various types of craniosynostoses. The patient exhibiting single suture synostosis that progresses to involve multiple sutures is distinctly uncommon, as is the patient exhibiting delayed synostosis involving all of the calvarial sutures. We report a group of 11 such patients with progressive and delayed holocalvarial synostosis. Most patients exhibited features of raised intracranial pressure or developmental delay, and in all patients symptoms were relieved after surgery. The diagnostic and therapeutic implications of this type of presentation in craniosynostosis are discussed.

Child↗
PubMed1985

Monoclonal antibodies to nerve growth factor from bovine seminal plasma.

Mouse monoclonal antibodies directed against nerve growth factor (beta NGF) from bovine seminal plasma have been isolated and characterized. They are produced by hybridomas derived from Sp2/0.Ag14 myeloma cells and spleen cells from BALB/c mice immunized with beta NGF which was purified by the method of Harper et al. [J. biol. Chem. 257, 8541-8548 (1982)]. Five of these hybridomas can be grown in ascites tumor form and secrete antibodies of the IgG1 or IgG2a subclass. When used to probe the components of seminal plasma extracts or purified beta NGF as separated electrophoretically on SDS gels, the antibodies react with the beta NGF band at Mr = 15,000. The antibodies bind to native bovine beta NGF, but bind very poorly to mouse beta NGF. Antibody exclusion and additive-binding experiments indicate that these antibodies bind to the 1 antigenic domain. The cell receptor binding site is probably not close to this domain, as the antibodies fail to block the biological activity of bovine beta NGF on cultures of dissociated neurons from sensory ganglia. These monoclonal antibodies define a region in which bovine beta NGF is structurally different from the closely related molecule mouse beta NGF.

Animals↗
PubMed1979

Cutaneous and venous complications of pentazocine abuse.

A 55-year-old man with a two-year history of intramuscular pentazocine abuse had classical cutaneous findings as well as secondary venous thrombosis, which, to our knowledge, is previously undescribed. Histologic evaluation, including direct immunofluorescent microscopy, did not establish the mechanism of tissue destruction.

Humans↗
PubMed1978

Fulminant necrotising enterocolitis associated with Clostridia.

5 infants with no growth of bacteria on cultures of blood and peritoneal fluid recovered from necrotising enterocolitis after medical treatment alone. 12 infants with positive cultures required surgery. 5 of these 12, who did not harbour clostridia, had a mild clinical course and all 5 survived segmental bowel resection. The 7 infants who harboured clostridia had a more severe clinical course and 4 died. In 3 of 4 infants with Clostridium perfringens, the necrotising enterocolitis was fulminant, characterised by severe pneumatosis intestinalis, extensive gangrene, early intestinal perforation, and a fatal outcome.

Ascitic Fluid↗
PubMed1978

Tonsillolith.

Explore the source record for details and available documents.

Calculi↗
PubMed1978

Lifted-weight difference thresholds as a function of hand.

A study was conducted to determine if the two hands of right-handers are differentially sensitive to changes in perceived weight. Using the method of limits, the left and right hands of 20 college students were tested at each of three reference weights: 90, 100, and 110 gm. Results indicated that, over-all, difference thresholds for the two hands were not reliably different, though a trend did emerge toward greater right-handed sensitivity to weight changes at smaller weights and greater left-handed sensitivity at greater weights.

Differential Threshold↗
PubMed1978

A conjugate of cellulase with fluorescein isothiocyanate: a specific stain for cellulose.

A fluorescent technique has been developed for in situ staining of cellulose. The staining agent in conjugate of cellulase and fluorescein isothiocyanate (FITC). Application of this agent does not disturb intercellular or intracellular substances. The technique depends on the specific binding of the fluorescent labeled enzyme to its substrate. The stain has been tested on cell-free noncellulose polysaccharides similar to cellulose and does not stain them. The technique has been used to localize cellulose during the life cycle of Dictyostelium discoideum with results that correspond to previous work using other methods.

Acetobacter↗