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H H Ho

Publications and source records attributed to H H Ho.

72 records · Page 4Linked to original sources
PubMed1984

Morphometry of cat's pulmonary arterial tree.

Morphometic data of the pulmonary artery in the cat's right lung are presented. Silicone elastomer casts of cat's right lung were made, and measured, counted and analyzed. The Strahler system is used to describe the branching pattern of the arterial vascular tree. These data are needed for any quantitative approach to the study of the pulmonary circulation. For all the pulmonary blood vessels of the cat lying between the main pulmonary artery and the capillary beds, there are a total of 10 orders of vessels in the right upper lobe, 9 orders of vessels in the right middle lobe and 11 orders of vessels in the right lower lobe. The ratio of the number of branches in successive orders of vessels or the branching ratio, is 3.58. The corresponding average diameter ratio is 1.72, whereas the average length ratio is 1.81.

Animals↗
PubMed1983

Patency and compliance of pulmonary veins when airway pressure exceeds blood pressure.

Our measurements on cat's lung show that pulmonary veins and venules are not collapsible, but remain open when the alveolar gas pressure (PA) exceeds the local blood pressure (Pv). Their compliance constants show no discontinuity as Pv falls below PA. The capillaries, however, do collapse when PA greater than Pv. The explanation of the patency of the veins when PA greater than Pv is the pulling on the blood vessels by tension in the interalveolar septa. Photomicrographs show that each venule (or vein) is pulled radially by three or more interalveolar septa. Capillary sheets, however, are exposed to gas on the lateral sides and can readily collapse when PA greater than Pv. These facts provide the key to the analysis of pulmonary blood flow in zone 2. The "sluicing" gate, i.e., the site of flow limitation, must be located at the junctions of capillary sheets and the first generation of venules. Further, data on the branching pattern and compliance of small pulmonary veins, which are needed in quantitative analysis of pulmonary circulation, are presented.

Animals↗
PubMed1983

Morphometry of cat pulmonary venous tree.

Morphometric data of the pulmonary veins in the cat right lung are presented. Silicone elastomer casts of the right lungs of five cats were made, measured, counted, and analyzed. The Strahler system is used to describe the branching pattern of the vascular tree. These data are needed for the physicomathematical approach to pulmonary circulation. For all the pulmonary blood vessels lying between the left atrium and the capillary beds, there are a total of 10 orders of vessels in the right upper lobe, 9 orders of vessels in the right middle lobe, and 11 orders of vessels in the right lower lobe. The ratios of the diameters, lengths, and the number of branches in successive orders of vessels are called the diameter, length, and branching ratios, respectively. For the cat pulmonary venous tree, the average branching ratio is 3.521, the average diameter ratio is 1.727, and the average length ratio is 2.402 for vessels of orders 1-3 and 1.532 for vessels of orders 4-10.

Animals↗
PubMed1981

Application of immunoperoxidase staining to more rapid detection and identification of rubella virus isolates.

Efforts were made to shorten the time required for detection of rubella virus in clinical materials through the use of immunoperoxidase (IP) staining. Comparative studies were performed in which specimens were inoculated in parallel into BHK-21 hamster kidney cells, which were examined by IP staining at 5 days, and into BK-13 and BS-C-1 cells, which were examined in two ways, viz., by subpassage at 7 days into BHK-21 cells and IP staining 3 days later and by subpassage at 7 days into BS-C-1 cells followed by interference testing and immunofluorescence (IF) staining on positive materials (standard method). Direct inoculation into BHK-21 cells with IP staining at 5 days permitted detection and identification of 59% of the 63 positive specimens. Toxicity of some specimens preserved with sorbitol and of certain tissue specimens reduced the number of satisfactory examinations which could be performed in this system. Virus detection and identification by IP staining on subpassaged RK-13 and BS-C-1 materials, requiring a total of 18 days, was comparable to the longer interference-IF method, requiring 17 days. Results obtained by IP staining and interference-IF showed 98% correlation on RK-13 materials and 97% correlation on BS-C-1 materials. IP staining on inoculated BHK-21 cells can be a useful method for rapid identification of a relatively high proportion of rubella-positive specimens, particularly if sorbitol-preserved specimens are avoided, and IP staining on subpassaged RK-13 and BS-C-1 materials is a highly satisfactory alternative to the longer interference-IF method.

Animals↗
PubMed1978

Comparative sensitivity of various cell culture systems for isolation of viruses from wastewater and fecal samples.

In efforts to define the most sensitive cell culture systems for recovery of viruses from wastewaters, 181 samples were inoculated in parallel into tube cultures of various cell types and were plaqued in bottle and petri dish cultures of three types of monkey kidney cells. Polioviruses were recovered most frequently in the RD line of human rhabdomyosarcoma cells, group A coxsackieviruses in RD and human fetal diploid kidney (HFDK) cells, group B coxsackieviruses in the BGM line of African green monkey kidney cells, echoviruses in RD and primary rhesus monkey kidney (RhMK) cells, and reoviruses in RhMK cells. BGM cells were unsatisfactory for recovery of viruses other than polioviruses and group B coxsackieviruses, and a line of fetal rhesus monkey kidney (MFK) was not a satisfactory substitute for primary RhMK. With RhMK cells, comparable numbers of virus isolations were made in tube cultures and in plaque assays conducted in bottle cultures, but with BGM and MFK cells, fewer isolations were made by plaquing than by inoculation of tube cultures. In comparative plaque assays on fecal samples under three different overlays in bottle and plate cultures of RhMK, BGM, and MFK cells, it was found that plaquing in the most sensitive system, RhMK, was less efficient for virus recovery than was inoculation of tube cultures of RhMK or HFDK cells. Overall, plaque assays performed in petri dishes in a CO(2) incubator yielded fewer virus isolates than did parallel plaque assays performed in closed bottle cultures. Other limitations of plaque assays for recovery of human enteric viruses are discussed.

Animals↗
PubMed1977

Lyophilized combination pools of enterovirus equine antisera: preparation and test procedures for the identification of field strains of 19 group A coxsackievirus serotypes.

This paper describes the preparation of seven combination pools of equine antisera, designated J though P, for identification of 19 coxsackievirus A immunotypes. Each pool is composed of 4 to 6 antisera; the serotypes included are A1-6, 8, 10-15, and 17-22. These pools, unlike the previously prepared A-H enterovirus pools, were lyophilized from volumes of 0.5 ml dispensed into 5-ml vials, and when rehydrated with 5 ml of diluent provide 50-antibody-unit material ready for use in identification tests without further dilution. Procedures for using the antiserum pools are given, and guidance is provided for interpreting the results of serum neutralization tests in identifying field isolates.

Animals↗
PubMed1975

Propagation and isolation of group A coxsackieviruses in RD cells.

The RD cell line, derived from a human rhabdomyosarcoma, supported replication of a number of group A coxsackieviruses, including types A5 and A6 which heretofore have been propagable only in suckling mice. A number of the group A coxsackievirus types which replicated in RD cells had higher titers in this cell line than in other cell culture systems. In tests on a limited number of clinical specimens, RD cells were slightly less sensitive than suckling mice for isolation of group A coxsackieviruses, but they did permit the recovery of certain virus types which previously could be isolated only in suckling mice. Group B coxsackieviruses replicated poorly or not at all in RD cells.

Animals↗
PubMed1973

Lyophilized combination pools of enterovirus equine antisera: preparation and test procedures for the identification of field strains of 42 enteroviruses.

This paper describes the preparation of 8 dried pools (designated A to H) of sera. Each pool is composed of 10 or 11 of 42 individual enterovirus equine sera and contains 500 antibody units of each serum component per 0.1 ml. Procedures for using the antiserum pools are given, and guidance is provided for interpreting the results of serum neutralization tests in identifying field isolates.

Animals↗
PubMed1971

Evaluation of enterovirus immune horse serum pools for identification of virus field strains.

Immune horse sera to 42 enterovirus immunotypes were pooled according to the Lim Benyesh-Melnick and the "intersecting serum" schemes. Each serum was diluted in the pools to contain 50 antibody units. After it was established that the pools correctly neutralized prototype virus strains, they were evaluated in tests against 273 enterovirus field strains representing most of the viral types included in the pools. With test virus doses of 10-100 TCD(50), most of the poliovirus and coxsackievirus field strains were correctly identified in both schemes, but a number of the echoviruses were neutralized by heterotypic pools, particularly in the Lim Benyesh-Melnick scheme. However, at higher test virus doses of 320-3200 TCD(50), little heterotypic neutralization occurred in either scheme, and 93-94% of the virus field strains were correctly identified in each scheme. With these larger virus doses, breakthrough tended to occur in homologous pools by the 7th day, but rarely by the 5th day. Since the Lim Benyesh-Melnick pool scheme employs 8 pools as compared with 13 for the intersecting serum scheme, and since the two schemes were equally satisfactory for identifying virus field strains at test virus doses of 320-3200 TCD(50), immune horse sera will be pooled by the former scheme, thus utilizing fewer pools, for distribution to qualified viral diagnostic laboratories.

Animals↗
PubMedDate not supplied

Fracture behavior of human mandibular incisors following endodontic treatment and porcelain veneer restoration.

PURPOSE: Because of existing controversy, the present study investigated the individual and combined effects of endodontic treatment and porcelain veneer restoration on the fracture behavior of human mandibular incisors. MATERIALS AND METHODS: Forty extracted intact human mandibular incisors were assigned to four groups of ten with a similar range of labiolingual widths at the cementoenamel junctions. Group A consisted of intact teeth; group B consisted of endodontically treated teeth; group C teeth were restored with labial porcelain veneers; and those of group D were endodontically treated and had labial porcelain veneers. All teeth were subjected to a slow continuous loading test at 30 degrees to the long axis of the teeth and 1 mm below the incisal edge on the labial side. RESULTS: Fracture forces were 415 +/- 220 N, 370 +/- 89 N, 420 +/- 128 N, and 448 +/- 156 N for groups A, B, C, and D, respectively. Root fracture was the most common mode of failure. There were no statistically significant differences between the groups in terms of fracture forces and modes of failure. CONCLUSION: Human mandibular incisors with endodontic treatment and/or porcelain veneer restorations were able to withstand the same magnitude of oblique loading as intact teeth. Endodontic treatment and/or porcelain veneer restoration did not affect the mode of failure of mandibular incisors.

Acid Etching, Dental↗