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Biomedical subjects

K L Huang

Publications and source records attributed to K L Huang.

26 records · Page 2Linked to original sources

Diving pattern of fishermen in the Pescadores.

Professional diving fishermen in the Pescadores Archipelago (119.30 degrees W, 23.30 degrees N) dive with a simple hookah system. Although they use modern equipment, such as wet suit, face mask, mouth piece with demand valve, spear gun, weight belt, and fins, their lack of knowledge of diving medicine is apparent. On the average, 180 cases of decompression sickness (DCS) per year were reported to occur in the Pescadores. We conducted studies in 1990 and 1992 on three islands of the Archipelago. At the time of our study, an estimated 140 diving fishermen resided on these three islands. Of the 62 fishermen interviewed, 14 volunteered for the recording of dive profiles using a diver-carried data logger. In the summer of 1990, a group of eight fishermen dived, on the average, to a depth of 17.8 +/- 5.3 m (mean +/- SD; range, 8-27 m) for 26.9 +/- 19.7 min (5-66 min). Although the diving depth was similar to that of the average recollections of 43 divers, 20.1 +/- 4.4 m (15-30 m), the actual diving time was far shorter than that of their recollections, 426 +/- 138 min (240-630 min). The post-typhoon sea floor conditions may have shortened their diving time. In the summer of 1992, a group of six fishermen dived to 20.5 +/- 3.8 m (15-26 m) for 56.4 +/- 21.2 min (18-84 min). Again, the diving depth matched that of their recollection well, 22.2 +/- 2.5 m (20-26 m), but their bottom time was far shorter than they believed, 270 +/- 108 min (120-480 min). They used no decompression procedures, regardless of the bottom time and diving depth. In the 1990 group, 5 out of 10 equivalent single dive bottom times (ESDBT) exceeded U.S. Navy no-decompression (No-D) air dive limits; whereas in the 1992 group, 7 out of 9 ESDBTs exceeded No-D limits. Eight of the 38 discrete dives exceeded the No-D limits, even if we underestimate their decompression stress by disregarding their repetitive dive history. However, no symptoms of DCS were observed in either the 1990 or 1992 groups of 14 divers, despite 63% of the ESDBTs and 21% of discrete dives having exceeded the No-D limits. Adaptation to diving work may have allowed them to exceed the established No-D limits. The existing records of incidence of DCS from this region suggest that previously they must have dived longer or deeper or both during times of abundant resources.

Adult↗

Spectral analysis of bubble sounds in decompressed guinea pigs.

Doppler ultrasonic monitoring was used to detect bubbles in sixteen guinea pigs subjected to a simulated air-dive profile of 9 ATA for 25 minutes. After completion of the decompression, eight subjects did not demonstrate any signs of decompression sickness (DCS), two developed paraplegia and six died. Under sedation, the Doppler ultrasonic bubble detector was placed precordially to record the bubble signals in both pre-dive and post-dive. The recorded signals were analyzed with a high resolution signal analyzer to compare changes between pre-dive and post-dive spectrograms. Bubble signals appeared in the frequency range between 0.64 +/- 0.02 KHz and 6.08 +/- 0.30 KHz. In terms of the net spectral level versus frequency areas (difference between pre-dive and post-dive spectrograms), the mean areas in the paraplegia group and the death group were significantly larger than those in the group without DCS. Therefore, we concluded that the spectral analysis may be an objective and quantitative adjunctive method to the interpretation of Doppler bubble signals.

Animals↗

Different relaxations between L-arginine and acetylcholine in spontaneously hypertensive rat aortae treated with N omega-nitro-L-arginine.

The relaxing effects of L-arginine and acetylcholine were compared on contracted thoracic aortic rings from Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) in the present study. Results demonstrated that both vasodilatations induced by L-arginine and acetylcholine in WKY were greater than those in SHR. The maximal relaxation induced by acetylcholine was greater than that induced by L-arginine in both WKY and SHR. However, the difference of relaxation induced by L-arginine was less than that induced by acetylcholine between WKY and SHR. In addition, phenylephrine caused contractions, which were similarly augmented after the removal of the endothelium or the treatment with N omega-nitro-L-arginine in aortic rings from WKY and SHR. On the aorta preparations from SHR a larger contraction was produced by phenylephrine and the maximal relaxations produced by L-arginine and acetylcholine were significantly reduced. These effects were not seen after the endothelium had been removed. We suggest that the ability of the endothelium to synthesize NO may be reduced in hypertension.

Acetylcholine↗

Antibody responses after influenza and pneumococcal immunization in HIV-infected homosexual men.

We conducted a study to assess the effect of human immunodeficiency virus (HIV) infection on humoral immunity. Fifty-five homosexual men and 19 heterosexual men had four- to six-week postimmunization antibody responses measured to trivalent influenza vaccine and 23-valent pneumococcal vaccine. The homosexual men were divided into three groups: 20 asymptomatic HIV-seronegative men, 10 asymptomatic HIV-seropositive men, and 25 HIV-seropositive men with persistent generalized lymphadenopathy. Antibody responses to influenza antigens in the subgroups of homosexual men did not significantly differ from those of heterosexual controls. The IgG antibody responses to pneumococcal capsular types 9N and 18C in men with lymphadenopathy, and type 18C in HIV-seronegative homosexual men, were lower than those of heterosexual controls. Otherwise, responses to other ten capsular types showed no significant differences. There was no evidence of an immunosuppressive effect of vaccination on T-cell numbers, or deterioration of clinical status associated with vaccination. This study demonstrates that HIV-infected homosexual men, asymptomatic or with persistent generalized lymphadenopathy, are able to mount appropriate antibody responses to two commonly used vaccines.

Acquired Immunodeficiency Syndrome↗

Antibody response after influenza immunization in renal transplant patients receiving cyclosporin A or azathioprine.

Nineteen renal transplant recipients receiving cyclosporin A and prednisone, eight kidney recipients receiving azathioprine and prednisone, and 12 healthy volunteers were immunized with 0.5 ml of trivalent influenza vaccine containing A/Bangkok/1/79 (H(3)N(2)), A/Brazil/11/78 (H(1)N(1)), and B/Singapore/222/79. Nine patients (47%) in the cyclosporin A group and five (63%) in the azathioprine group showed fourfold rises in titer to at least one virus strain compared with 12 (100%) in the control group.

Antibodies, Viral↗

Transfer of reaction inhibition.

A serious challenge to Hull's (1943) theory of reminiscence and intertrial-interval effects is posed by the current contention that reactive inhibition (In) must be task-specific since it does not seem to transfer from one task to another. This notion was examined within the framework of a practice-rest paradigm in which three control groups were given 20 1-min trials on a principal task with intertrial intervals of 0, 5, and 70 sec, respectively, while two experimental groups practiced alternately on the principal task and a secondary task known to produce evidence for I(R). The two secondary tasks varied in their similarities to the principal task. Additional control groups were used to assess the magnitude of habit transfer effects. The total sample consisted of 70 males and 70 females whose modal age was 18 yr. With habit transfer effects controlled, results showed clearly that work effects transferred from the alternate tasks to the main task without regard for differences in similarity. Thus, the task-specificity hypothesis was not supported.

Journal Article↗