High-throughput discovery of organic cages and catenanes using computational screening fused with robotic synthesis

Supramolecular synthesis is a powerful strategy for assembling complex molecules, but to do this by targeted design is challenging. This is because multicomponent assembly reactions have the potential to form a wide variety of products. High-throughput screening can explore a broad synthetic space, but this is inefficient and inelegant when applied blindly. Here we fuse computation with robotic synthesis to create a hybrid discovery workflow for discovering new organic cage molecules, and by extension, other supramolecular systems. A total of 78 precursor combinations were investigated by computation and experiment, leading to 33 cages that were formed cleanly in one-pot syntheses. Comparison of calculations with experimental outcomes across this broad library shows that computation has the power to focus experiments, for example by identifying linkers that are less likely to be reliable for cage formation. Screening also led to the unplanned discovery of a new cage topology-doubly bridged, triply interlocked cage catenanes.

Tumour oxygenation is increased by hyperthermia at mild temperatures. 1996

The effects of hyperthermia on the oxygenation status in R3230 AC tumours of Fischer rats were measured using a polarographic oxygen electrode system. The median pO(2) in about 10 mm diameter tumours grown s.c. in the leg of rats was 3.7 +/- 0.3 mm Hg and it significantly increased upon heating at modest temperatures. For example, the tumour pO(2) measured within 10-15 min after heating for 30 min at 42.5 degrees C was about three-fold greater than that in the control tumours. About 62% of pO(2) values measured in control tumours were <5 mm Hg. After heating at 42.5 degrees C for 30 min, 37% of pO(2) values were <5 mm Hg. Such an increase in tumour oxygenation or reoxygenation of hypoxic cells appeared to result from an increase in tumour blood flow caused by the mild temperature hyperthermia. The presence of hypoxic cells in tumours is believed to be a major factor in limiting the effectiveness of radiotherapy, certain chemotherapy drugs and phototherapy. Hyperthermia at mild temperatures easily achievable with the use of presently available clinical hyperthermia devices may be an effective means to overcome the hypoxic protection in the treatment of human tumours.

Changes in oxygenation status and blood flow in a rat tumor model by mild temperature hyperthermia

PURPOSE

Experiments were conducted to elucidate the relationship between the changes in oxygen partial pressure (pO2) and blood flow in heated tumors with an ultimate goal of using mild temperature hyperthermia (MTH) to increase tumor oxygenation.

METHODS AND MATERIALS

The blood flow and pO2 in the R3230 adenocarcinoma grown (subcutaneously) in the right hind limbs of Fischer rats were measured immediately or 24 h after heating at 40.5 degrees-43.5 degrees C for 30 or 60 min. The blood flow was measured with the radioactive microsphere method and the tumor pO2 was measured polarographically using an Eppendorf pO2 histograph.

RESULTS

The tumor PO2 significantly increased immediately and 24 h after heating for 30 min at 40.5 degrees-43.5 degrees C or for 60 min at 40.5 degrees and 41.5 degrees C. On the other hand, in tumors heated at 42.5 degrees C for 60 min, the tumor pO2 immediately after heating was similar to the control value whereas that 24 h after heating was about threefold greater than the control tumor pO2. Heating at 43.5 degrees C for 60 min resulted in a significant decline in pO2 immediately after and 24 h after heating. The increase in tumor pO2 immediately after heating appeared to be due to an increase in tumor blood flow. However, the changes in tumor pO2 and tumor blood flow 24 h after heating, particularly after high thermal doses (e.g., 60 min heating at 42.5 degrees or 43.5 degrees C), were not correlated.

CONCLUSION

Heating at mild temperatures (i.e., 40.5 degrees-42.5 degrees C for 30-60 min), caused thermal dose-dependent increases in pO2 in the R3230 AC tumors of Fischer rats during 0-24 h after heating. Such an increase in tumor oxygenation after MTH appeared to be due to an increase in tumor blood flow.

Recognizing factitious hypoglycemia in the family practice setting

BACKGROUND

Factitious hypoglycemia is a deliberate attempt to induce a low serum glucose level using either insulin or oral hypoglycemic agents. Sulfonylurea-induced hypoglycemia is more common than incidents of insulin abuse, and hypoglycemia caused by these oral agents is biochemically indistinguishable from insulinoma.

METHODS

We describe a case of factitious hypoglycemia resulting from insulin abuse in an adult diabetic patient, review the essentials of glucose homeostasis, and describe diagnostic tests that allow a differential diagnosis.

RESULTS AND CONCLUSION

Factitious hypoglycemia is associated with a higher incidence of suicide, depression, and personality disorders. Insulin-induced hypoglycemia can be detected by an insulin to C-peptide ratio that is greater than 1.0. In the absence of proof to the contrary, insulinoma should be considered the cause of hypoglycemia until another diagnosis is established. The generally poor prognosis for patients with factitious hypoglycemia underscores the importance of early recognition of factitious disorders.

Reduction of tumour blood flow with KB-R8498 potentiates the response of tumours to hyperthermia

The anti-tumour activity and the effect on tumour and normal tissue perfusion of a newly discovered anticancer agent, KB-R8498 (Kanebo Ltd., Osaka, Japan), were investigated in FSa II tumours of C3H mice. The tumour perfusion, as measured by the 86Rb-uptake method, markedly decreased with relatively little change in the normal tissue perfusion after an i.v. injection of KB-R8498. Furthermore, the drug potentiated the effect of hyperthermia at 42.5 degrees C for 60 min to suppress the tumour growth. The results suggest that the preferential reduction in tumour blood flow relative to normal tissue blood flow by KB-R8498 may be exploited to enhance the anti-tumour effect of hyperthermia.

HITS: a short domestic violence screening tool for use in a family practice setting

BACKGROUND AND OBJECTIVES

Domestic violence is an important problem that is often not recognized by physicians. We designed a short instrument for domestic violence screening that could be easily remembered and administered by family physicians.

METHODS

In phase one of the study, 160 adult female family practice office patients living with a partner for at least 12 months completed two questionnaires. One questionnaire was the verbal and physical aggression items of the Conflict Tactics Scale (CTS). The other was a new four-item questionnaire that asked respondents how often their partner physically Hurt, Insulted, Threatened with harm, and Screamed at them. These four items make the acronym HITS. In phase two, 99 women, who were self-identified victims of domestic violence, completed the HITS.

RESULTS

For phase one, Cronbach's alpha was .80 for the HITS scale. The correlation of HITS and CTS scores was .85. For phase two, the mean HITS scores for office patients and abuse victims were 6.13 and 15.15, respectively. Optimal data analysis revealed that a cut score of 10.5 on the HITS reliably differentiated respondents in the two groups. Using this cut score, 91% of patients and 96% of abuse victims were accurately classified.

CONCLUSIONS

The HITS scale showed good internal consistency and concurrent validity with the CTS verbal and physical aggression items. The HITS scale also showed good construct validity in its ability to differentiate family practice patients from abuse victims. The HITS scale is promising as a domestic violence screening mnemonic for family practice physicians and residents.

Tumor oxygenation after mild-temperature hyperthermia in combination with carbogen breathing: dependence on heat dose and tumor type

We investigated the effect of hyperthermia at 40.5-42.5 degrees C as well as the combination of hyperthermia and carbogen breathing on oxygenation in the SCK murine mammary carcinoma. In addition, the important question of how long the effect of heating on tumor oxygenation lasts was addressed in both SCK and FSaII (murine fibrosarcoma) tumors. The median pO2 in control SCK tumors was 4.4 +/- 0.2 mm Hg, and it increased to a maximum of 12.6 +/- 1.2 mm Hg when the tumors were heated at 41.5 degrees C for 1 h. Carbogen breathing increased the median pO2 of SCK tumors to 17.1 +/- 1.4 mm Hg, but after heating at 41.5 degrees C, it elevated the pO2 in SCK tumors markedly to 31.3 +/- 4.2 mm Hg. The kinetics of the return to baseline oxygenation after hyperthermia was found to vary with the type of tumor and the heat dose. The pO2 of FSaII tumors remained significantly higher than that of control tumors 24 h after heating at 41.5 degrees C for 60 min. The pO2 of SCK tumors remained elevated for up to 3 h after heating at 41.5 degrees C for 30 min, but if the tumors were heated for 60 min at this temperature, the median oxygen tension declined to the control level within 1 h after heating. It was concluded that mild-temperature hyperthermia, i.e. 41.5 degrees C, alone and in combination with carbogen breathing dramatically improves the oxygenation of these murine tumors and that the tumor type influences the duration of changes in oxygenation induced by mild-temperature hyperthermia.

Improvement of tumor oxygenation status by mild temperature hyperthermia alone or in combination with carbogen

The effects of mild temperature hyperthermia (MTH) on the oxygenation and radioresponse in rodent tumors were investigated. FSall tumors grown in the legs of C3H mice and R3230 AC tumors grown in the legs of Fischer rats were heated with a water bath and the partial pressure of oxygen (pO2) was determined using the microelectrode method. In FSall tumors, the pO2 measured immediately after heating at 41.5 degrees C for 1 hour was markedly higher than that in the control tumors, whereas heating at higher temperatures for 1 hour decreased the tumor oxygenation. In R3230 AC tumors, heating at 41.5 degrees C for 1 hour caused a moderate increase in the pO2 and heating at 42.5 degrees or 43.5 degrees C for 30 minutes markedly increased the pO2. However, heating at 42.5 degrees C or higher temperatures for 1 hour decreased the pO2 in the R3230 AC tumors. The improvement of oxygenation in FSall tumors by heating at 41.5 degrees C for 1 hour increased the radiation-induced cell death in these tumors. The combination of carbogen breathing with MTH was far more potent than carbogen breathing or MTH alone in increasing tumor oxygenation and potentiating the radiation effect in FSall tumors.

Tumour pO2 can be increased markedly by mild hyperthermia

We have studied the feasibility of improving tumour oxygenation with hyperthermia at modest temperatures which are achievable with the use of presently available clinical hyperthermia machines. FSaII tumours grown s.c. in the leg of C3H mice and R3230 AC tumours grown s.c. in the leg of Fischer rats were heated with a water bath and the tumour pO2 was determined with an Eppendorf pO2 histograph. The median pO2 in 7-8 mm diameter control FSaII tumours was 6.5 +/- 0.5 mmHg and it increased to 16.6 +/- 1.1 mmHg when the tumours were heated at 41.5 degrees C for 1 h. The median pO2 in 10 mm diameter control R3230 AC tumours was 3.7 +/- 0.3 mmHg. Heating at 42.5 degrees C for 30 min increased the median pO2 in the R3230 AC tumours to 12.2 +/- 1.8 mmHg. The pO2 in FSaII tumours measured 24 h after heating at 41.5 degrees C for 1 h was still higher than the pO2 before heating. The % frequency of pO2 values lower than 5 mmHg decreased markedly when the tumours were heated at the modest temperatures mentioned above. Modest temperature hyperthermia (MTH) may be an efficient and useful means to improve the oxygenation of human tumours.

Tumour oxygenation is increased by hyperthermia at mild temperatures

The effects of hyperthermia on the oxygenation status in R3230 AC tumours of Fischer rats were measured using a polarographic oxygen electrode system. The median pO2 in about 10 mm diameter tumours grown s.c. in the leg of rats was 3.7 +/- 0.3 mm Hg and it significantly increased upon heating at modest temperatures. For example, the tumour pO(2) measured within 10-15 min after heating for 30 min at 42.5 degrees C was about three-fold greater than that in the control tumours. About 62% of PO(2) values measured in control tumours were < 5 mm Hg. After heating at 42.5 degrees C for 30 min, 37% of PO(2) values were < 5 mm Hg. Such an increase in tumour oxygenation or reoxygenation of hypoxic cells appeared to result from an increase in tumour blood flow caused by the mild temperature hyperthermia. The presence of hypoxic cells in tumours is believed to be a major factor in limiting the effectiveness of radiotherapy, certain chemotherapy drugs and phototherapy. Hyperthermia at mild temperatures easily achievable with the use of presently available clinical hyperthermia devices may be an effective means to overcome the hypoxic protection in the treatment of human tumours.

Circadian variation of 5-fluorouracil and cis-platinum toxicity in mice

Circadian variations of organ specific and lethal toxicities were investigated in female C3H mice following intraperitoneal injection(s) of 5-fluorouracil (5-FU) and/or cis-platinum (CDDP) with different doses at one of the four equidistant time points, viz., 3, 9, 15 and 21 HALO (Hours After Light On). Lethality, peripheral WBC count, spleen size, femoral bone marrow cell population and changes in body weight were analyzed. A single injection of 5-FU (300 mg/kg) showed 45% mortality with 3 HALO and 15% with 9 HALO treatment (p < 0.05); that with CDDP (16 mg/kg) was 80% in 3 HALO and 10% in 9 HALO group (p < 0.01). Peripheral WBC count on the 4th post-treatment day showed that drug induced leukopenia was less severe with 15 HALO dosing compared to the other HALO points (p < 0.01). The reduction in spleen size following treatment was maximum in 3 HALO treated group with both drugs (p < 0.01). The combination therapy of these two drugs also showed circadian variation of toxicity. The results suggest that the toxic effects of chemotherapy are dosing time dependent.